2024/10/12 更新

写真a

トヤマ アキラ
外山 聡
TOYAMA Akira
所属
医歯学総合病院 薬剤部 教授
医歯学総合研究科 地域疾病制御医学専攻 教授
職名
教授
外部リンク

学位

  • 博士(薬学) ( 1999年11月   東北大学 )

研究キーワード

  • 共鳴ラマン分光法

  • 医療薬学

研究分野

  • ライフサイエンス / 医療薬学

経歴

  • 新潟大学   医歯学総合病院 薬剤部   教授

    2015年7月 - 現在

  • 新潟大学   医歯学総合研究科 地域疾病制御医学専攻   教授

    2015年7月 - 現在

  • 新潟大学   医歯学総合研究科 医科学専攻   教授

    2015年7月 - 現在

  • 新潟大学   医歯学総合病院   准教授

    2005年6月 - 2015年6月

  • 新潟大学   医歯学総合研究科 医科学専攻   准教授

    2005年6月 - 2015年6月

  • 新潟大学   医歯学総合研究科 地域疾病制御医学専攻   准教授

    2005年6月 - 2015年6月

▶ 全件表示

所属学協会

 

論文

  • Hospital pharmacist interventions for the management of oral mucositis in patients with head and neck cancer receiving chemoradiotherapy: a multicenter, prospective cohort study. 国際誌

    Kensuke Yoshida, Shinichi Watanabe, Naoto Hoshino, Kyongsun Pak, Noriaki Hidaka, Noboru Konno, Masaki Nakai, Chinami Ando, Tsuyoshi Yabuki, Naoto Suzuki, Kouji Katsura, Kei Tomihara, Akira Toyama

    Supportive care in cancer : official journal of the Multinational Association of Supportive Care in Cancer   31 ( 5 )   316 - 316   2023年5月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    PURPOSE: Oral mucositis is a severe adverse event in patients with head and neck cancer (HNC) receiving chemotherapy and radiotherapy that may cause the termination of cancer treatment. In this study, we aimed to reveal the benefits of pharmacist interventions in oral health care for patients with HNC receiving concurrent chemoradiotherapy (CCRT). METHODS: We conducted a multicenter, prospective cohort study on 173 patients from September 2019 to August 2022. We evaluated the association between the occurrence of oral mucositis during CCRT and various factors in the absence or presence of direct medication instructions from hospital pharmacists. RESULTS: Sixty-eight patients received medication instructions from pharmacists (the pharmacist intervention group), whereas 105 patients did not receive instructions (the control group). Logistic regression analysis showed that grade 2 (Gr 2) oral mucositis was significantly lower in patients receiving pharmacist interventions than in patients in the control group (adjusted odds ratio [aOR], 0.42; 95% confidence interval [CI], 0.18-0.96; P = 0.04). The time to onset of Gr 2 oral mucositis was significantly longer in the pharmacist intervention group than in the control group (hazard ratio, 0.53; 95% CI, 0.29-0.97; P = 0.04). CONCLUSION: Direct intervention, especially when provided by hospital pharmacists, can have a real effect in supporting patients with HNC experiencing severe side effects of treatments. Moreover, the integration of pharmacists into the oral healthcare team is becoming even more essential to reduce the severity of side effects.

    DOI: 10.1007/s00520-023-07784-6

    PubMed

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  • 切除不能膵がんに対するゲムシタビン+ナブパクリタキセル療法の長期継続に寄与する因子に関する調査

    小竹 正晃, 坂井 由紀, 新木 貴大, 鈴木 直人, 外山 聡

    日本病院薬剤師会雑誌   59 ( 5 )   519 - 524   2023年5月

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    記述言語:日本語   出版者・発行元:(一社)日本病院薬剤師会  

    切除不能膵がんの治療法であるゲムシタビン+ナブパクリタキセル療法(以下,GnP療法)臨床試験の無増悪生存期間中央値は5.5ヵ月と報告されている。新潟大学医歯学総合病院にて,GnP療法の180日の継続可否で,外来通院の患者団を2群化し後方視的に調査した。単変量解析よりp<0.15となる項目を説明変数とし,多重ロジスティック回帰分析を行った結果,総ビリルビン値が低いことと血小板値が高いことが,継続に寄与する独立因子であった。Receiver operating characteristic解析によるカットオフ値を用いたところ,治療開始時の総ビリルビン値とγ-グルタミルトランスペプチダーゼ値が低く,血清アルブミン値と血小板値が高い場合,GnP療法を長く継続できる可能性を示す回帰式が得られた。陽性的中率,陰性的中率,感度,特異度は各々80.0%,76.9%,66.7%,87.0%であった。(著者抄録)

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    その他リンク: https://search.jamas.or.jp/default/link?pub_year=2023&ichushi_jid=J04451&link_issn=&doc_id=20230511280012&doc_link_id=%2Fdg4hppha%2F2023%2F005905%2F012%2F0519-0524%26dl%3D0&url=https%3A%2F%2Fwww.medicalonline.jp%2Fjamas.php%3FGoodsID%3D%2Fdg4hppha%2F2023%2F005905%2F012%2F0519-0524%26dl%3D0&type=MedicalOnline&icon=https%3A%2F%2Fjk04.jamas.or.jp%2Ficon%2F00004_2.gif

  • HIV外来診療における協働意思決定に基づいた継続的な薬剤師介入の影響

    成田 綾香, 島田 泉, 鈴木 直人, 外山 聡

    医療薬学   49 ( 2 )   39 - 50   2023年2月

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    記述言語:日本語   出版者・発行元:(一社)日本医療薬学会  

    ヒト免疫不全ウイルス(HIV)の外来診療における協働意思決定に基づいた継続的な薬剤師面談の有効性を評価した。2016年10月~2018年3月の間に当院HIV外来を定期受診した抗レトロウイルス療法(ART)継続中の患者49名を対象とした。このうち、処方変更が不要であると判断された11名(男性10名、女性1名、中央値48歳)を変更提案不要群、薬剤師面談において処方変更を提案した38名(男性30名、女性8名、中央値45.5歳)を変更提案群、変更提案群のなかで処方変更がなされた35名を変更群と定義した。ARTの錠数、併用服薬錠数、服薬総錠数、服薬種類数は処方変更後に有意に減少し、推奨ART、single table regimenの適応となった患者数は有意に増加した。ART変更理由は、多い順に副作用・長期毒性の回避・軽減、服薬負担軽減、薬物相互作用回避、薬価負担軽減であった。継続的な薬剤師面談によって、治療安全性の向上、服薬アドヒアランス維持、経済的負担軽減が得られることが示唆された。

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    その他リンク: https://search.jamas.or.jp/default/link?pub_year=2023&ichushi_jid=J03520&link_issn=&doc_id=20230216220001&doc_link_id=%2Fdb5pharm%2F2023%2F004902%2F001%2F0039-0050%26dl%3D0&url=https%3A%2F%2Fwww.medicalonline.jp%2Fjamas.php%3FGoodsID%3D%2Fdb5pharm%2F2023%2F004902%2F001%2F0039-0050%26dl%3D0&type=MedicalOnline&icon=https%3A%2F%2Fjk04.jamas.or.jp%2Ficon%2F00004_2.gif

  • 薬の副作用に関する患者アンケート多施設調査 1997年度と2019年度の比較検討

    俵山 悟, 古川 智康, 清水 健一, 翁長 寛人, 大瀧 翔太, 井上 幹雄, 関口 知行, 坂口 正幸, 藤井 星也, 山寺 徹, 根津 洋平, 細川 浩輝, 阿部 佑一, 鈴木 光幸, 持田 知志, 八木 元広, 清水 英勇, 渡辺 重雄, 若林 聰一, 二階堂 雅一, 山田 徹, 稲月 幸範, 外山 聡, 宇野 勝次, 新潟医薬品安全性研究会

    医薬品安全性学   8 ( 2 )   127 - 139   2022年12月

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    記述言語:日本語   出版者・発行元:(一社)日本医薬品安全性学会  

    背景・目的:新潟医薬品安全性研究会(本研究会)は,医薬品の副作用発生の実態を把握するために,1997年度に医薬品の副作用に関する多施設患者アンケート調査を実施した.そこで,20年以上経過した2019年度も副作用に関するアンケート調査を行い,今後の本研究会の医薬品副作用の取り組む指針を見出すことを目的に,1997年度のアンケート調査結果と比較検討した.方法:本研究会参加の新潟市近郊の病院9施設と保険薬局6施設83店舗の計15施設でアンケート調査を実施した.アンケートの対象者は,病院では外来および入院患者,保険薬局では処方箋調剤患者で,アンケート協力を口頭で同意を得られた16歳以上を対象者とした.全8問のアンケート用紙を配布し,患者自身による記述式とした.結果:2019年度の副作用既往率は,23.1%を示し,1997年度と比べて有意差を認めなかった.2019年度の副作用症状も皮膚障害>消化器障害>神経障害の順で,1997年度とほとんど変化はなかった.2019年度の副作用原因薬は抗菌薬と解熱鎮痛消炎薬の頻度が上昇し,両者で50%以上を占めた.2019年度の副作用原因薬剤名の認知度は約1.8倍上昇し(P<0.01,χ2-test),副作用発現時の対処では「相談相手が薬剤師」が約5倍上昇した(P<0.001,χ2-test).結論:20年以上経過して医薬品副作用の既往率に変化はみられないが,これは,1990年からの本研究会の活動により,もともと低い数字を維持し続けていた可能性が考えられる.また,副作用原因薬剤名の認知度が上昇し,副作用発現時の対処で「相談相手が薬剤師」が上昇したのは本研究会の活動の成果と考えられる.薬剤師は「医薬品のリスクから患者を守る」というJASDSの目的の主旨に基づいて,ドラッグセーフティーマネージャー(DSM)として医薬品の安全性確保のスキルを身に付け,副作用マネジメントをさらに積極的に取り組んでいく必要があると考える.(著者抄録)

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  • 薬に対する患者の意識 新潟県下多施設調査

    大瀧 翔太, 古川 智康, 清水 健一, 翁長 寛人, 俵山 悟, 細川 浩輝, 鈴木 光幸, 持田 知志, 八木 元広, 渡辺 重雄, 若林 聰一, 山田 徹, 稲月 幸範, 井上 幹雄, 関口 知行, 坂口 正幸, 藤井 星也, 山寺 徹, 根津 洋平, 阿部 佑一, 清水 英勇, 二階堂 雅一, 外山 聡, 宇野 勝次, 新潟医薬品安全性研究会

    医薬品安全性学   8 ( 2 )   109 - 118   2022年12月

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    記述言語:日本語   出版者・発行元:(一社)日本医薬品安全性学会  

    背景・目的:新潟医薬品安全性研究会は,適正な医薬品情報の提供と医薬品の安全性を確保する目的で,1997年度に薬に対する患者の意識調査(アンケート調査)を実施した.その結果をもとに医薬品の安全性の向上への介入を20年以上実施してきた.そこで,現在の患者の薬に対する意識を把握し,今後の本研究会の取り組み方の指針を見出すことを目的に,2019年度にアンケート調査を実施して検討した.方法:本研究会参加の新潟市近郊の病院9施設と保険薬局83店舗(6社)の計15施設でアンケート調査を実施した.対象者は,病院は外来および入院患者,保険薬局では処方箋調剤患者で,アンケートの協力を口頭で得られた16歳以上を対象に全10問のアンケート用紙を配布し,患者自身に記述してもらった.結果:薬への関心頻度は,73.7%であり,薬への心配頻度は,61.8%であった.関心頻度と心配頻度から算出した医療機関への信頼・安心頻度は,11.8%であった.関心内容と心配内容は極めて強い相関性(r=0.936,P<0.01)を認めたが,副作用だけが関心よりも心配の頻度が上回った.結論:薬への関心頻度が高値を示したのは,薬剤師による薬剤情報提供の推進や医薬分業率の上昇による成果だと考えられる.しかし,薬への心配頻度も同様に高値を示し,医療機関への信頼・安心は低値を示した.したがって,薬剤師は臨床の場で医薬品の副作用マネジメントをさらに推し進める必要がある.(著者抄録)

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  • オピオイドで疼痛管理不良の放射線皮膚炎にリドカイン混合ワセリンが奏効した1例

    島田 泉, 工藤 範子, 外山 美央, 市川 紘将, 土田 裕子, 岩井 由樹, 鈴木 丈雄, 結城 明彦, 濱 菜摘, 外山 聡

    日本緩和医療薬学雑誌   15 ( 1 )   21 - 24   2022年3月

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    記述言語:日本語   出版者・発行元:(一社)日本緩和医療薬学会  

    リドカインゼリーを混合したワセリンを塗布することで放射線皮膚炎による激しい疼痛を明瞭に軽減できた症例を報告する。今回の症例では、放射線皮膚炎の疼痛にオピオイドやステロイド外用剤を用いたが、疼痛コントロールに苦慮していた。リドカイン混合ワセリンは、放射線皮膚炎による難治性の疼痛を軽減(NRS9→3)する。(著者抄録)

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  • [Comparison between Single and Three Times Pre-operative Administration of Amoxicillin in the Prophylactic Effects for Surgical Site Infections in Japanese Patients with Mandibular Third Molars Extraction].

    Kensuke Yoshida, Yasumitsu Kodama, Chie Saito, Kei Tomihara, Akira Toyama

    Yakugaku zasshi : Journal of the Pharmaceutical Society of Japan   142 ( 12 )   1391 - 1398   2022年

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)  

    Although the dosage of oral antibiotics (OA) for the mandibular third molar extraction (MTME) varies among the administration periods according to the current guideline, our previous reports suggested that it might be possible to further shorten the administration period without increasing the incidence of surgical site infection (SSI). In the present study, we retrospectively evaluated the relationship between the incidence of SSI and the administration period of OA in patients who underwent the MTME in our hospital. This retrospective cohort study included 348 patients who underwent the MTME in our dental outpatient clinic from June 2020 to March 2022. The administrated antibiotic was amoxicillin (AMPC) in all patients. Patients were divided into two groups based on the administration period of AMPC single and three times before the surgery. The following information was collected: (1) patient factors (age, gender, body mass index, diagnosis, mandibular third molar status); (2) surgical factors (operation time, presence/absence of wound closure, presence/absence of hemostat, experience of surgeons); (3) relationship between administration period of OA and SSI occurrence; and (4) details of SSI. There were 217 cases in the single group and 131 cases in the three times group. The incidence of SSI was 1.1% (4/348), with 1.4% (3/217) in the single group and 0.8% (1/131) in the three times group; there was no significant difference between the two groups. Our result suggests that single administration of AMPC before the MTME would be sufficient for the prevention of SSI in Japanese patients without risk factors.

    DOI: 10.1248/yakushi.22-00163

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  • Salivary inflammatory mediators as biomarkers for oral mucositis and oral mucosal dryness in cancer patients: A pilot study. 国際誌

    Anna Kiyomi, Kensuke Yoshida, Chie Arai, Risa Usuki, Kyosuke Yamazaki, Naoto Hoshino, Akira Kurokawa, Shinobu Imai, Naoto Suzuki, Akira Toyama, Munetoshi Sugiura

    PloS one   17 ( 4 )   e0267092   2022年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Oral mucositis (OM) is a common side effect in patients with cancer receiving chemotherapy and radiotherapy; however, no salivary mediator is known to be associated with OM. We aimed to determine candidate salivary inflammatory mediators potentially associated with OM in patients with cancer. To this end, we compared the relationships between OM grade, oral mucosal dryness, and inflammatory mediators (Interleukin (IL)-1β, IL-6, IL-10, IL-12p70, tumor necrosis factor (TNF), prostaglandin E2, and vascular endothelial growth factor) in patients with cancer and in healthy volunteers (HV). We collected saliva samples from 18 patients with cancer according to the following schedule: 1) within 14 days of treatment initiation, 2) within 3 days of OM occurrence, 3) when OM was improved or got worsened, and 4) within 7 days after chemotherapy completion. The oral care support team determined the OM grade at each sample collection point based on CTCAE version 5.0. Salivary inflammatory mediator concentrations were detected using cytometric bead array or enzyme-linked immunoassay. We compared oral mucosal dryness in pre- and post-index patients with cancer to that in HV (n = 33) using an oral moisture-checking device. Fourteen of eighteen patients experienced OM (four, grade 3 OM; four, grade 2 OM; six, grade 1 OM). IL-6, IL-10, and TNF salivary concentrations were significantly increased in the post-index group compared to those in the pre-index group (p = 0.0002, p = 0.0364, and p = 0.0160, respectively). Additionally, salivary IL-6, IL-10, and TNF levels were significantly higher in the post-index group than in the HV group (p < 0.0001, p < 0.05, and p < 0.05, respectively). Significant positive correlations were observed between OM grade and salivary IL-6, IL-10, and TNF levels (p = 0.0004, r = 0.4939; p = 0.0171, r = 0.3394; and p = 0007, r = 0.4662, respectively). Oral mucosal dryness was significantly higher in the HV than in the pre- and post-index groups (p < 0.001). Our findings suggest that salivary IL-6, IL-10, and TNF levels may be used as biomarkers for OM occurrence and grade in patients with cancer. Furthermore, monitoring oral mucosal dryness and managing oral hygiene before cancer treatment is essential.

    DOI: 10.1371/journal.pone.0267092

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  • Comparison between the prophylactic effects of amoxicillin 24 and 48 hours pre-operatively on surgical site infections in Japanese patients with impacted mandibular third molars: A prospective cohort study. 国際誌

    Kensuke Yoshida, Yasumitsu Kodama, Atsushi Nishikawa, Andrea Rei Estacio Salazar, Akira Toyama, Ritsuo Takagi

    Journal of infection and chemotherapy : official journal of the Japan Society of Chemotherapy   27 ( 6 )   845 - 851   2021年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    INTRODUCTION: According to the guidelines, the dosage for mandibular wisdom tooth extraction (MWTE) varies within the administration period. There is a 24-fold difference between the minimum and maximum doses. If an appropriate antimicrobial can be administered without increasing incidence of surgical site infection (SSI), it may lead to a global action plan on antimicrobial resistance (AMR). Therefore, we prospectively surveyed incidence of SSI post-operatively and use of oral antibiotics (OA) for MWTE. METHODS: Subjects were patients who underwent MWTE in our dental outpatient clinic from May 2019 to April 2020. Two groups were formed depending on type of administration period they received: 24 h and 48 h after surgery. The following information was collected: (1) patient factors (age, gender, body mass index, presence/absence of preoperative medication, diagnosis, impacted wisdom tooth status; (2) surgical factors (operative time, presence/absence of closure, presence/absence of hemostat, doctor career, type and frequency of painkiller); (3) relationship between administration period of OA and SSI occurrence; and (4) details of SSI. RESULTS: Three hundred forty subjects were analyzed, all of which used amoxicillin. There were 106 cases in 24 h group and 234 cases in 48 h group. The total incidence of SSI was 1.1% (4/340 cases), with 0.9% (1/106 cases) in 24 h group and 1.3% (3/234 cases) in 48 h group; there was no difference between the two groups. CONCLUSION: Our study suggests that amoxicillin (250 mg/dose every 8 h x 3 doses beginning 1 h before surgery) might be sufficient in preventing SSI in Japanese dental patients without SSI risk factors.

    DOI: 10.1016/j.jiac.2021.01.018

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  • Clinico-statistical survey of oral antimicrobial prophylaxis and surgical site infection regarding ordinary tooth extraction and mandibular wisdom tooth extraction in the dental outpatient clinic. 国際誌

    Kensuke Yoshida, Yasumitsu Kodama, Takahiro Nagai, Andrea Rei Estacio Salazar, Syouta Kaneko, Chie Saito, Akira Toyama, Ritsuo Takagi

    Journal of infection and chemotherapy : official journal of the Japan Society of Chemotherapy   27 ( 2 )   192 - 197   2021年2月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    INTRODUCTION: We investigated the use of oral antibiotics (OA) and surgical site infection (SSI) related to extractions of ordinary teeth and mandibular wisdom teeth in a dental outpatient clinic from January 2015 to December 2019. METHODS: The following information were surveyed: (1) presence/absence of OA, (2) timing, (3) type, (4) administration period, and (5) SSI rates. RESULTS: The use of OA during ordinary tooth extraction decreased from 68.3% to 41.3%, but SSI rate did not change during this period of time. Total SSI rate was 0.8% (122/14,832) on average. For mandibular wisdom tooth extraction, preoperative administration of third-generation cephalosporins decreased from 70.4% to 0.3% while that of penicillin (AMPC) increased from 0% to 98%. SSI rate was not changed after these improvements. Total SSI rate was 3.5% (180/5106) on average. The duration of OA was slightly decreased to two days in 2018 and 2019, and it was found that there was no significant difference in SSI rates between 2- and 3-day durations. Preoperative administration had 0.37 odds ratio (OR) (95% confidence interval (95%CI): 0.22-0.63) of SSI compared with postoperative administration. AMPC had 0.76 OR (95% CI: 0.55-1.04) of SSI compared with Third-generation cephalosporins and others. Timing of OA was P < 0.01. CONCLUSIONS: SSI rates did not change over time, administration period of OA decreased and the use of AMPC increased. Therefore, it seems necessary to continue to investigate the effects of SSI risk factors proactively in the future and to make efforts in the advocacy of appropriate antimicrobial use.

    DOI: 10.1016/j.jiac.2020.08.022

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  • Pharmacist involved education program in a multidisciplinary team for oral mucositis: Its impact in head-and-neck cancer patients. 国際誌

    Kensuke Yoshida, Yasumitsu Kodama, Yusuke Tanaka, Kyongsun Pak, Marie Soga, Akira Toyama, Kouji Katsura, Ritsuo Takagi

    PloS one   16 ( 11 )   e0260026   2021年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    OBJECTIVES: This retrospective study examined how a pharmacist-involved education program in a multidisciplinary team (PEMT) for oral mucositis (OM) affected head-and-neck cancer (HNC) patients receiving concurrent chemoradiotherapy (CCRT). MATERIALS AND METHODS: Total samples data of 53 patients during the stipulated timeframe were retrospectively collected from electronic medical records from February 2017 to January 2019. We compared the presence/absence of OM (OM: yes/no) between patients with and without PEMT (PEMT: yes/no) as the primary endpoint and OM severity as the secondary endpoint. The following information was surveyed: age, gender, weight loss, steroid or immunosuppressant use, hematological values (albumin, white blood cell count, blood platelets, and neutrophils), cancer grade, primary cancer site, type and use of mouthwash and moisturizer, opioid use (yes/no, days until the start of opioid use, and dose, switch to tape), and length of hospital day (LOD). The two groups were compared using Fisher's exact test for qualitative data and the Mann-Whitney U test for quantitative data, and a significance level of p<0.05 was set. RESULTS: The group managed by PEMT had significantly lower weight loss and a significantly lower incidence of local anesthetic and opioid use and switch to tape compared with the group not managed by PEMT (p<0.05). The two groups showed no significant difference in OM (yes/no) or OM severity. The PEMT group had significantly shorter LOD at 57 (53-64) days compared with the non-PEMT group at 63.5 (57-68) days (p<0.05). CONCLUSIONS: Our results showed that PEMT did not improve OM (yes/no) or OM severity in HNC patients undergoing CCRT. However, the PEMT group had a lower incidence of grades 3 and 4 OM than the non-PEMT group, although not significantly. In addition, PEMT contributed to oral pain relief and the lowering of the risk for OM by reduction in weight loss.

    DOI: 10.1371/journal.pone.0260026

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  • Prediction of Postoperative Infection for Patients Undergoing Gastrointestinal Surgery: Findings from Electronic Health Records

    Kyoko Nakazawa, Takashi Ishikawa, Akira Toyama, Toshifumi Wakai, Kohei Akazawa

    Gastroenterology Insights   11 ( 2 )   36 - 46   2020年11月

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    掲載種別:研究論文(学術雑誌)   出版者・発行元:MDPI AG  

    Introduction: Postoperative infection is a major cause of morbidity and prolonged hospitalization in patients undergoing gastrointestinal surgery. This observational study aimed to investigate the risk factors associated with postoperative infection and to develop a prediction model for postoperative infections that occur after gastrointestinal surgery. Methods: The study population comprised 1637 patients who underwent gastrointestinal surgery at Niigata University Medical and Dental Hospital between June 2013 and May 2017. Observational data from 1883 surgical procedures were used in the statistical analyses (including 198 patients who underwent several operations). Results: The generalized estimating equation (GEE) was used to detect significant risk factors, including older age, history of smoking, body temperature greater than 38 °C, non-endoscopic surgical procedures, surgery in the thoracic or lower gastrointestinal tract, and use of medical nutritional products during surgery. The sensitivity and specificity of the GEE model were 88.2% and 55.1%, respectively. Conclusion: This study established a predictable GEE model, incorporating the data of patients who were hospitalized several times into a prediction analysis, even though the sensitivity was not sufficiently high. The GEE model, which is considered clinically useful, can be constructed using a variety of variables, including those obtained from electronic health records.

    DOI: 10.3390/gastroent11020007

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  • A case of severe hepatotoxicity induced by cisplatin and 5-fluorouracil. 国際誌

    Ayaka Yaegashi, Kensuke Yoshida, Naoto Suzuki, Izumi Shimada, Yusuke Tani, Yasuo Saijo, Akira Toyama

    International cancer conference journal   9 ( 1 )   24 - 27   2020年1月

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    記述言語:英語  

    Severe hepatotoxicity from combination chemotherapy with cisplatin and 5-fluorouracil is a rare adverse effect. In this case report, we present a case with severe hepatotoxicity immediately following chemotherapy with cisplatin and 5-fluorouracil. This female patient had previously been treated with this combination with no hepatotoxicity. The elevated liver enzymes quickly normalized after chemotherapy was stopped. There were no specific changes in liver imaging. As hepatotoxicity occurred after repeated administration of cisplatin, we suggest that this hepatotoxicity might represent a case of allergic hepatitis caused by cisplatin. Severe hepatotoxicity should be watched for with repeated administration of cisplatin.

    DOI: 10.1007/s13691-019-00394-2

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  • Age-Based Comparison of Hematological Toxicity in Patients with Lung Cancer. 国際誌

    Yuki Sakai, Qiliang Zhou, Yoshifumi Matsumoto, Takuro Saiki, Masato Moriyama, Akira Toyama, Yasuo Saijo

    Oncology   98 ( 11 )   771 - 778   2020年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    INTRODUCTION: Because of the increasing age of the general population, there is an increasing number of older patients with lung cancer. Cancer chemotherapy often causes severe hematological toxicity in older patients. OBJECTIVE: This study aimed to explore the risk factors affecting the hematological toxicity of cytotoxic anticancer drugs in patients with lung cancer. METHODS: Data were retrospectively collected from 194 patients with lung cancer at Niigata University Medical and Dental Hospital, Japan, between April 2011 and March 2016, when the patients underwent their first round of cytotoxic chemotherapy. The patients were divided into three groups on the basis of age: <65, 65-74, and ≥75 years. Physiological functions and laboratory data before treatment, as well as hematological adverse events following chemotherapy, were compared among the groups. RESULTS: Patients aged ≥75 years were significantly more likely to experience grade 3 or 4 neutropenia, compared with patients aged <65 years. However, there were no differences in the incidence of anemia or thrombocytopenia among the age groups. The frequency of febrile neutropenia tended to increase with age. Multivariate analysis showed that age ≥75 years, male sex, and a performance status of ≥2 were independent factors for grade 3 or 4 neutropenia. Patients with 2 or 3 of these factors had a significantly higher frequency of neutropenia, compared with patients who had 0 or 1 of these factors. CONCLUSION: We found that age ≥75 years, male sex, and a performance status of ≥2 were independent risk factors for grade 3 or 4 neutropenia.

    DOI: 10.1159/000507864

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  • 歯科領域における周術期患者の抗菌薬使用実態調査 経口スイッチ療法の評価

    吉田 謙介, 田村 隆, 磯辺 浩和, 新木 貴大, 中川 裕介, 石田 みなみ, 鈴木 直人, 西川 敦, 船山 昭典, 児玉 泰光, 小林 正治, 高木 律男, 田邊 嘉也, 外山 聡

    医薬品相互作用研究   41 ( 3 )   174 - 177   2017年11月

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    記述言語:日本語   出版者・発行元:(一社)医薬品相互作用研究会  

    当院歯科領域では周術期患者に対し、術後感染予防として注射用抗菌薬セファゾリン(CEZ)が推奨されているが、CEZ投与終了翌日から経口抗菌薬へ切り替えて投与する治療(経口スイッチ療法)が経験的に行われる場合がある。「術後感染予防抗菌薬適正使用のための実践ガイドライン」では、推奨投与期間を超えた経口抗菌薬の追加は不要であるとされている。そこで今回、経口スイッチ療法の必要性について検討するため、2015年1月~6月に当院歯科領域でCEZを使用された患者213例を対象とし、経口スイッチ療法実施群(111例)と非実施群(102例)に分けて諸データの群間比較を行った。結果、実施群の背景として、「入院期間の短縮」や「剤形変更による費用削減」などを期待して経口スイッチ療法が行われていたと考えられたが、実際には「入院期間の短縮」「費用削減」とも認められなかった。このことから経口スイッチ療法の必要性は低い可能性が示唆された。

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  • ICT介入による予防的抗菌薬の変更が口腔外科手術におけるSSI発生率と医療費に与える影響

    吉田 謙介, 鈴木 直人, 新木 貴大, 西川 敦, 児玉 泰光, 高木 律男, 田邊 嘉也, 外山 聡

    日本病院薬剤師会雑誌   53 ( 6 )   671 - 674   2017年6月

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    記述言語:日本語   出版者・発行元:(一社)日本病院薬剤師会  

    これまで新潟大学医歯学総合病院歯科領域では予防的抗菌薬として、経験的にセフォチアム(cefotiam:以下、CTM)が使用されていたが、院内感染制御チーム(infection control team:以下、ICT)が2011年7月に介入し、セファゾリン(cefazolin:以下、CEZ)へ変更となった。今回、予防的抗菌薬変更による手術部位感染(surgical site infection:以下、SSI)発生率と医療費への影響を評価することを目的に後ろ向きに調査した。その結果、対象患者1,081名中、CTM使用患者は486名、CEZ使用患者は595名で、SSI発生率に差はなかった。一人当たりの平均投与費用は9,946円から2,169円へと減少し、SSI発生阻止率から算出した費用対効果比は10,016.3から2,204.5に改善されていた。以上のことから、ICTの介入による予防的抗菌薬変更はSSI発生率に差は認められず、医療費削減の点からも推奨される取り組みであったと考えられた。(著者抄録)

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    その他リンク: https://search.jamas.or.jp/default/link?pub_year=2017&ichushi_jid=J04451&link_issn=&doc_id=20170612190005&doc_link_id=%2Fdg4hppha%2F2017%2F005306%2F002%2F0671-0674%26dl%3D0&url=https%3A%2F%2Fwww.medicalonline.jp%2Fjamas.php%3FGoodsID%3D%2Fdg4hppha%2F2017%2F005306%2F002%2F0671-0674%26dl%3D0&type=MedicalOnline&icon=https%3A%2F%2Fjk04.jamas.or.jp%2Ficon%2F00004_2.gif

  • Immune monitoring with a lymphocyte adenosine triphosphate assay in kidney transplant recipients treated with a calcineurin inhibitor. 国際誌

    Kentaro Sugiyama, Mahoto Tsukaguchi, Akira Toyama, Hiroshi Satoh, Kazuhide Saito, Yuki Nakagawa, Kota Takahashi, Sachiko Tanaka, Kenji Onda, Toshihiko Hirano

    Experimental and clinical transplantation : official journal of the Middle East Society for Organ Transplantation   12 ( 3 )   195 - 9   2014年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    OBJECTIVES: The adenosine triphosphate assay using peripheral lymphocytes may be useful to evaluate the risks of acute rejection and infection in kidney transplant patients. We used the adenosine triphosphate assay to evaluate differences between recipients who were treated with cyclosporine- or tacrolimus-based immunosuppressive therapy. MATERIALS AND METHODS: Adenosine triphosphate levels were measured in peripheral CD4+ cells before and after transplant and were correlated with clinical outcomes in 45 kidney transplant recipients. These recipients received immunosuppressive therapy with either cyclosporine (23 patients) or tacrolimus (22 patients). RESULTS: Adenosine triphosphate levels were significantly lower in the cyclosporine- than tacrolimus-based therapy groups from 2 to 6 weeks after transplant. Adenosine triphosphate levels were similar between these groups before and 1 week after transplant. The frequency of cytomegalovirus infection was greater in the recipients who received cyclosporine (17 patients [74%]) than tacrolimus (6 patients [27%]; P ≦ .003). The frequency of acute rejection episodes was similar between the cyclosporine and tacrolimus groups. CONCLUSIONS: These observations suggest that cyclosporine-based immunosuppressive therapy causes excessive immunosuppression compared with tacrolimus-based therapy, evidenced by the lymphocyte adenosine triphosphate levels. The adenosine triphosphate assay using peripheral CD4+ cells may be a useful method for predicting the occurrence of cytomegalovirus infections in kidney transplant recipients.

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  • Peripheral Lymphocyte Response to Mycophenolic Acid In Vitro and Incidence of Cytomegalovirus Infection in Renal Transplantation. 国際誌

    Kentaro Sugiyama, Hiroyasu Sasahara, Mahoto Tsukaguchi, Kazuya Isogai, Akira Toyama, Hiroshi Satoh, Kazuhide Saitoh, Yuki Nakagawa, Kota Takahashi, Sachiko Tanaka, Kenji Onda, Toshihiko Hirano

    Cell medicine   6 ( 1-2 )   47 - 55   2013年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    The lymphocyte immunosuppressant sensitivity test (LIST) with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay procedure has been used to predict the pharmacological efficacy of immunosuppressive agents to prevent acute rejection episodes for renal transplant recipients. In this study, mycophenolic acid (MPA) pharmacological efficacies were evaluated by LIST at both prior to and just after renal transplantation. We compared the efficacies to the clinical outcome of these recipients. MPA's pharmacological efficacy was evaluated by LIST not only before the operation but also at 2, 4, and 6 weeks after transplantation in 16 renal transplant recipients. These recipients were divided into high- and low-sensitivity groups according to peripheral blood mononuclear cell (PBMC) sensitivity to MPA in vitro. The MPA sensitivities were compared to cytomegalovirus (CMV) infection and acute rejection episodes in these recipients under MPA immunosuppressive therapy. The rate of CMV infection episodes in the low-MPA pharmacological efficacy group categorized at 2 weeks after renal transplantation was 5/6 (83.3%), which was significantly higher than the rate of 1/10 (10.0%) (p < 0.01) in the high-MPA sensitivity group. However, the MPA pharmacological efficacy evaluated both before and after transplantation had no relationship with the incidence of rejection episodes. These findings suggest that the MPA pharmacological efficacy evaluated by LIST at 2 weeks after operation is a useful biomarker for predicting the following occurrence of CMV infection episodes in renal transplant recipients.

    DOI: 10.3727/215517913X674216

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  • Comparison of the Pharmacological Efficacies of Immunosuppressive Drugs Evaluated by the ATP Production and Mitochondrial Activity in Human Lymphocytes. 国際誌

    Hiroyasu Sasahara, Kentaro Sugiyama, Mahoto Tsukaguchi, Kazuya Isogai, Akira Toyama, Hiroshi Satoh, Kazuhide Saitoh, Yuki Nakagawa, Kota Takahashi, Sachiko Tanaka, Kenji Onda, Toshihiko Hirano

    Cell medicine   6 ( 1-2 )   39 - 45   2013年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    The lymphocyte immunosuppressant sensitivity test (LIST) using patient peripheral lymphocytes can predict the therapeutic efficacy of immunosuppressive drugs used in renal transplantation. We have evaluated the pharmacological efficacy of drugs by using the LIST with the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay, which measures the cellular mitochondrial activity. The LIST with the MTT assay requires a relatively large amount of blood. As such, we developed a new assay for examining drug sensitivity with a CellTiter-Glo assay, which measures the amount of cellular ATP to help increase the assay's sensitivity and reduce the amount of blood needed. Renal transplant recipients generally receive either cyclosporine or tacrolimus, in addition to mycophenolate mofetil and methylprednisolone, as an immunosuppressive therapy to prevent acute rejection. We evaluated the pharmacological efficacy of these immunosuppressive agents with both the MTT and CellTiter-Glo assays using the peripheral blood mononuclear cells of 21 healthy volunteers. Furthermore, we also examined the relationship between these immunosuppressive agents' pharmacological efficacy and the results of the MTT and CellTiter-Glo assays. The IC50 values for cyclosporine, tacrolimus, mycophenolic acid, and methylprednisolone were significantly correlated between the MTT and CellTiter-Glo assays. The amount of blood cells required for LIST with the CellTiter-Glo assay was able to be reduced to 25% of the amount required for the previously established LIST with the MTT assay procedure. We concluded from these observations that the LIST with the CellTiter-Glo assay should be used instead of the MTT assay for carrying out individualized immunosuppressive therapy in renal transplantation patients.

    DOI: 10.3727/215517913X674207

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  • Clinical Significance of the Pharmacological Efficacy of Tacrolimus Estimated by the Lymphocyte Immunosuppressant Sensitivity Test (LIST) Before and After Renal Transplantation. 国際誌

    Kentaro Sugiyama, Kazuya Isogai, Akira Toyama, Hiroshi Satoh, Kazuhide Saito, Yuki Nakagawa, Masayuki Tasaki, Kota Takahashi, Toshihiko Hirano

    Cell medicine   3 ( 1-3 )   81 - 88   2012年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    The lymphocyte immunosuppressant sensitivity test (LIST) with the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay procedure can predict the pharmacological efficacy of immunosuppressive agents. A previous study reported the pharmacological efficacy of tacrolimus evaluated by LIST just before renal transplantation significantly correlated with the incidence of acute rejection episodes. However, the pharmacological efficacy of tacrolimus has not been estimated after renal transplantation. Therefore, the present study evaluated the pharmacological efficacy of tacrolimus by LIST using the MTT assay procedure before and 1, 3, and 12 months after transplantation in 17 renal transplant recipients that received tacrolimus-based immunosuppressive therapy. The tacrolimus pharmacological efficacies before and after the procedure were also compared with incidence of acute rejection and cytomegalovirus (CMV) infection episodes. The individual values of tacrolimus 50% inhibition of lymphocyte proliferation (IC50) varied widely before transplantation, and the mean value of the IC50 was 126.4 ± 337.7 ng/ml. The patients were divided into two groups according to the tacrolimus IC50 values evaluated before transplantation. The rate of acute rejection episodes in the tacrolimus high-sensitivity group was significantly lower than that in the tacrolimus low-sensitivity group (p = 0.005). The tacrolimus IC50 deviation between patients expanded further at one and three months after surgery. However, the sensitivity deviation almost converged at 1 year after surgery. Moreover, the pharmacological efficacy of tacrolimus evaluated at 1, 3, and 12 months after transplantation did not significantly correlate with the incidence of acute rejection episodes. The pharmacological efficacies of tacrolimus evaluated at both before and after surgery were not significantly correlated with the episodes of CMV infection. These findings suggest that the pharmacological efficacy of tacrolimus evaluated with LIST before surgery is a useful biomarker for predicting the occurrence of acute allograft rejection in renal transplantation.

    DOI: 10.3727/215517912X639360

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  • Comparative study of the cellular pharmacodynamics of tacrolimus in renal transplant recipients treated with and without basiliximab. 国際誌

    Kentaro Sugiyama, Kazuya Isogai, Satoshi Horisawa, Akira Toyama, Hiroshi Satoh, Kazuhide Saito, Yuki Nakagawa, Masayuki Tasaki, Kota Takahashi, Toshihiko Hirano

    Cell transplantation   21 ( 2-3 )   565 - 70   2012年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Basiliximab is a recently developed immunosuppressive agent for the prevention of acute allograft rejection in renal transplant recipients. The combination use of basiliximab and a calcineurin inhibitor was suggested to be more effective in comparison to immunosuppressive therapy using calcineurin inhibitor without basiliximab. Cyclosporine has been generally administered with basiliximab for renal transplant recipients. However, in cases of tacrolimus-based immunosuppressive regimen, the clinical efficacy and safety of combined use of tacrolimus and basiliximab remains to be elucidated. This study evaluated the tacrolimus pharmacological efficacy using a lymphocyte immunosuppressant sensitivity test (LIST) with MTT assay procedures in 16 cases of renal transplant recipients treated by tacrolimus without basiliximab and in 13 cases treated by tacrolimus in combination with basiliximab. The rate of acute rejection episodes in the recipients treated with tacrolimus plus basiliximab was 1/13 (7.7%), whereas the rate in the recipients treated with tacrolimus without basiliximab was 6/16 (37.5%). The recipients were divided into two groups according to their peripheral blood mononuclear cell (PBMC) sensitivity to tacrolimus [i.e., including a tacrolimus high sensitivity group (IC(50) <1.0 ng/ml) and a low sensitivity group (IC(50) >1.0 ng/ml). In the recipients treated with tacrolimus without basiliximab, the rate of acute rejection episodes in the tacrolimus high sensitivity group was 1/10 (10.0%), which was significantly lower than the rate in the low sensitivity group of 5/6 (83.3%; p = 0.008). The incidence of cytomegalovirus infection was not significantly different between the tacrolimus high and the low sensitivity groups of the recipients treated with tacrolimus with and without basiliximab. Therefore, in the case of selected tacrolimus-based immunosuppressive therapy for renal transplant recipients, the tacrolimus pharmacological efficacy should be evaluated using LIST at a time just before the transplant procedure in order to accurately predict allograft rejection. The data also suggested that low tacrolimus sensitivity recipients should be treated with tacrolimus-based immunosuppressive therapy in combination with basiliximab.

    DOI: 10.3727/096368911X605493

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  • [Longer working hours of pharmacists in the ward resulted in lower medication-related errors--survey of national university hospitals in Japan].

    Kazuo Matsubara, Akira Toyama, Hiroshi Satoh, Hiroshi Suzuki, Toshio Awaya, Yoshikazu Tasaki, Toshiaki Yasuoka, Ryuya Horiuchi

    Yakugaku zasshi : Journal of the Pharmaceutical Society of Japan   131 ( 4 )   635 - 41   2011年4月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)  

    It is obvious that pharmacists play a critical role as risk managers in the healthcare system, especially in medication treatment. Hitherto, there is not a single multicenter-survey report describing the effectiveness of clinical pharmacists in preventing medical errors from occurring in the wards in Japan. Thus, we conducted a 1-month survey to elucidate the relationship between the number of errors and working hours of pharmacists in the ward, and verified whether the assignment of clinical pharmacists to the ward would prevent medical errors between October 1-31, 2009. Questionnaire items for the pharmacists at 42 national university hospitals and a medical institute included the total and the respective numbers of medication-related errors, beds and working hours of pharmacist in 2 internal medicine and 2 surgical departments in each hospital. Regardless of severity, errors were consecutively reported to the Medical Security and Safety Management Section in each hospital. The analysis of errors revealed that longer working hours of pharmacists in the ward resulted in less medication-related errors; this was especially significant in the internal medicine ward (where a variety of drugs were used) compared with the surgical ward. However, the nurse assignment mode (nurse/inpatients ratio: 1 : 7-10) did not influence the error frequency. The results of this survey strongly indicate that assignment of clinical pharmacists to the ward is critically essential in promoting medication safety and efficacy.

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  • The pharmacological efficacy of mycophenolic acid before and after renal transplantation as estimated by the lymphocyte immunosuppressant sensitivity test (LIST). 国際誌

    Kentaro Sugiyama, Kazuya Isogai, Satoshi Horisawa, Akira Toyama, Hiroshi Satoh, Kazuhide Saito, Yuki Nakagawa, Masayuki Tasaki, Kota Takahashi, Toshihiko Hirano

    Immunopharmacology and immunotoxicology   32 ( 3 )   430 - 6   2010年9月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    The lymphocyte immunosuppressant sensitivity test (LIST) can predict the pharmacological efficacy of immunosuppressive agents. We herein estimated the mycophenolic acid efficacy using LIST before and 1, 3, and 12 months after the operation in 15 renal transplant recipients. The pharmacological efficacy of mycophenolic acid as assessed before transplantation showed small individual variations, whereas the variability greatly increased at 1 and 3 months after transplantation. Furthermore, the individual IC50 variation among these subjects at 1-year after operation was closely similar to that observed before surgery. No significant implications of these individual differences in the mycophenolic acid sensitivity were noted in regard to the clinical courses of these recipients.

    DOI: 10.3109/08923970903490478

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  • Pharmacodynamic parameters of immunosuppressive drugs are not correlated with age, duration of dialysis, percentage of lymphocytes or lymphocyte stimulation index in renal transplant recipients.

    Kentaro Sugiyama, Kazuya Isogai, Akira Toyama, Hiroshi Satoh, Kazuhide Saito, Yuki Nakagawa, Masayuki Tasaki, Kota Takahashi, Noriko Saito, Toshihiko Hirano

    Biological & pharmaceutical bulletin   31 ( 11 )   2146 - 9   2008年11月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    The lymphocyte immunosuppressant-sensitivity test (LIST) has been reported extensively as being able to estimate the pharmacological efficacy of immunosuppressive drugs in individual patients. This study measured the IC50 values for 6 drugs, cyclosporine, tacrolimus, methylprednisolone, 6-mercaptopurine, mycophenolic acid, and mizoribine, against mitogen-induced proliferation of peripheral-blood lymphocytes in 29 renal transplant recipients. We also examined relationship between the IC50 values and 4 factors; age, duration of dialysis, percentage of lymphocytes in total white blood cells, and blastogenesis stimulation index by mitogen. There were no significant correlations between the IC50 values and these factors, except that the tacrolimus IC50 value was correlated weakly with the stimulation index (p<0.05, r=-0.429). It was concluded that the pharmacological efficacy of immunosuppressive drugs cannot be inferred from the patient characteristics or their laboratory data. LIST is an effective method to elucidate the pharmacodynamic properties of immunosuppressive agents in individual renal transplant recipients without being influenced by the recipient clinical data.

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MISC

  • Binding affinity and mode of distamycin A with A/T stretches in double-stranded DNA: importance of the terminal A/T residues. 国際誌

    Mariko Asagi, Akira Toyama, Hideo Takeuchi

    Biophysical chemistry   149 ( 1-2 )   34 - 9   2010年6月

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    記述言語:英語  

    Distamycin A (Dst) is an antibiotic which binds to the minor groove of double-stranded DNA at A/T-rich regions. We have examined the affinity and mode of Dst binding to DNA duplexes containing a conserved A/T core and variable terminal A/T regions by using circular dichroism spectroscopy. The observed circular dichroism spectra were analyzed by singular value decomposition and fitted to a two-step binding model. The result clearly shows a correlation between the affinity for Dst and the preference for Dst-DNA 1:1 binding over 2:1 binding. The A/T stretches that prefer 1:1 binding form high-affinity 1:1 complexes, whereas those preferring 2:1 binding form stable 2:1 complex with low overall affinities. The terminal A/T residues of the Dst binding region play an important role in the stabilization/destabilization of the 1:1 and 2:1 complexes, resulting in a terminal residue-dependent variation of the binding affinity and the binding mode preference.

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  • Activation of lactoperoxidase by heme-linked protonation and heme-independent iodide binding. 国際誌

    Akira Toyama, Aya Tominaga, Tatsuo Inoue, Hideo Takeuchi

    Biopolymers   93 ( 1 )   113 - 20   2010年1月

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    記述言語:英語  

    Lactoperoxidase (LPO), a mammalian secretory heme peroxidase, catalyzes the oxidation of thiocyanate by hydrogen peroxide to produce hypothiocyanate, an antibacterial agent. Although LPO is known to be activated at acidic pH and in the presence of iodide, the structural basis of the activation is not well understood. We have examined the effects of pH and iodide concentration on the catalytic activity and the structure of LPO. Electrochemical and colorimetric assays have shown that the catalytic activity is maximized at pH 4.5. The heme Soret absorption band exhibits a small red-shift at pH 5.0 upon acidification, which is ascribable to a structural transition from a neutral to an acidic form. Resonance Raman spectra suggest that the heme porphyrin core is slightly contracted and the Fe-His bond is strengthened in the acidic form compared to the neutral form. The structural change of LPO upon activation at acidic pH is similar to that observed for myeloperoxidase, another mammalian heme peroxidase, upon activation at neutral pH. Binding of iodide enhances the catalytic activity of LPO without affecting either the optimum pH of activity or the heme structure, implying that the iodide binding occurs at a protein site away from the heme-linked protonation site.

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  • Interactions between histidine and tryptophan residues in the BM2 proton channel from influenza B virus. 国際誌

    Kohei Otomo, Akira Toyama, Takashi Miura, Hideo Takeuchi

    Journal of biochemistry   145 ( 4 )   543 - 54   2009年4月

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    記述言語:英語  

    The BM2 protein of influenza B virus forms a transmembrane proton channel essential for the virus infection. We investigated the structure and mechanism of the BM2 proton channel by using a 31-mer peptide (BM2-TMP) representing the putative transmembrane domain of BM2, with special focus on His19, Trp23 and His27. Like the full-length protein, BM2-TMP formed a transmembrane proton channel activated at acidic pH with a midpoint of transition at pH 6.4 +/- 0.1. Mutation of His19 to Ala almost abolished the channel activity, whereas the His27-to-Ala mutant retained partial activity. The proton selectivity of the channel was lost upon substitution of Phe for Trp23. Comparison of CD, fluorescence and Raman spectra measured for wild-type and mutated BM2-TMP at varied pH showed the pK(a) of the imidazole ring to be approximately 6.5 for His19 and approximately 7.6 for His27. Analysis of the pH-dependent fluorescence and Raman intensities suggested the occurrence of cation-pi interaction between the protonated imidazole ring of His and the indole ring of Trp. The His19-Trp23 cation-pi interaction below pH 6.5 is likely to trigger the opening of the proton channel, whereas His27 is not essential but enhances the channel activity through interaction with Trp23, which constitutes the proton-selective gate.

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  • Evidence for the cation-pi interaction between Cu2+ and tryptophan. 国際誌

    Hanami Yorita, Kohei Otomo, Hirotsugu Hiramatsu, Akira Toyama, Takashi Miura, Hideo Takeuchi

    Journal of the American Chemical Society   130 ( 46 )   15266 - 7   2008年11月

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    記述言語:英語  

    The cation-pi interaction, a noncovalent interaction of electrostatic nature between a cation and an electron-rich pi system, is increasingly recognized as an important force that influences the structures and functions of molecules including proteins. Unlike other metal cations, the transition metal cation Cu2+ is not regarded to take part in a cation-pi interaction because Cu2+ tends to oxidize the pi electron system, in particular that of Trp, and to introduce covalency in the metal-pi electron interaction. This paper reports the first spectral evidence for the cation-pi interaction between Cu2+ and Trp. The Cu2+ ion bound to the amino N-terminal Cu2+/Ni2+ binding motif composed of three amino acid residues interacts with the indole ring of the fourth Trp residue in a noncovalent manner. The Cu2+-Trp interaction produces a distinct negative band at 223 nm in circular dichroism (CD), which disappears upon mutation or depletion of the Trp residue or upon replacement of the Cu2+ ion by Ni2+. In UV absorption, a pair of negative/positive intensity changes is generated at 222/231 nm by the Cu2+-Trp interaction, being consistent with the previous observations on the indole ring interacting with K+ or a cationic His imidazole ring. The negative CD band around 223 nm is characteristic of the Cu2+-Trp pair and may be useful as a marker of the Cu2+-Trp cation-pi interaction. Coordination of negatively charged ligands to Cu2+ is suggested to be important for the cation to be involved in a cation-pi interaction.

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  • Bead-like passage of chloride ions through ClC chloride channels. 国際誌

    Atsushi Suenaga, Jay Z Yeh, Makoto Taiji, Akira Toyama, Hideo Takeuchi, Mingyu Son, Kazuyoshi Takayama, Masatoshi Iwamoto, Ikuro Sato, Toshio Narahashi, Akihiko Konagaya, Kunihiko Goto

    Biophysical chemistry   120 ( 1 )   36 - 43   2006年3月

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    記述言語:英語  

    The ClC chloride channels control the ionic composition of the cytoplasm and the volume of cells, and regulate electrical excitability. Recently, it has been proposed that prokaryotic ClC channels are H+-Cl- exchange transporter. Although X-ray and molecular dynamics (MD) studies of bacterial ClC channels have investigated the filter open-close and ion permeation mechanism of channels, details have remained unclear. We performed MD simulations of ClC channels involving H+, Na+, K+, or H3O+ in the intracellular region to elucidate the open-close mechanism, and to clarify the role of H+ ion an H+-Cl- exchange transporter. Our simulations revealed that H+ and Na+ caused channel opening and the passage of Cl- ions. Na+ induced a bead-like string of Cl- -Na+-Cl--Na+-Cl- ions to form and permeate through ClC channels to the intracellular side with the widening of the channel pathway.

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  • Copper reduction by the octapeptide repeat region of prion protein: pH dependence and implications in cellular copper uptake. 国際誌

    Takashi Miura, Satoshi Sasaki, Akira Toyama, Hideo Takeuchi

    Biochemistry   44 ( 24 )   8712 - 20   2005年6月

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    The physiological function of the prion protein (PrP) remains enigmatic despite its established involvement in the pathogenesis of spongiform encephalopathies. PrP is a glycolipid-anchored membrane protein, which constitutively recycles between the cell surface and an endosomal compartment. The N-terminal region of PrP contains a four tandem repeat (OP4) of the octapeptide PHGGGWGQ (OP) that binds and reduces Cu(II) ions. We have examined the kinetic properties of the OP4-mediated Cu(II) reduction and found that OP4 exhibits the highest reduction activity around pH 6.5, close to the pH in early endosomes. All four OP units and at least one tryptophan side chain are essential for Cu(II) reduction. The reaction is described by an uncompetitive substrate inhibition mechanism involving a 1:1 Cu(II)-OP4 active intermediate. Structural analysis by Raman spectroscopy has revealed that the Cu(II) ion is coordinated by four histidine Ntau atoms in the active intermediate and the feasibility of formation of this intermediate correlates with the Cu(II) reduction over a pH range from 5.0 to 8.2. Molecular mechanics calculations suggest that two tryptophan residues of OP4 are located near the Cu(II) site, being consistent with the importance of redox-active tryptophan in the Cu(II) reduction. PrP has been proposed to capture Cu(II) ions in the extracellular space and release them in the endosome. The results of this study strongly suggest that PrP also plays a role in the reduction of captured Cu(II) ions prior to their transfer to Cu(I)-specific intracellular copper trafficking proteins.

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  • Catalytic and structural role of a metal-free histidine residue in bovine Cu-Zn superoxide dismutase 国際誌

    A Toyama, Y Takahashi, H Takeuchi

    BIOCHEMISTRY   43 ( 16 )   4670 - 4679   2004年4月

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    記述言語:英語   出版者・発行元:AMER CHEMICAL SOC  

    Cu-Zn superoxide dismutase (SOD) contains a conserved, metal-free His residue at an opening of the backbone beta-barrel in addition to six Cu- and/or Zn-bound His residues in the active site. We examined the protonation and hydrogen bonding state of the metal-free His residue (His41) in bovine SOD by UV Raman spectroscopy. Analysis of the His Raman intensity at 1406 cm(-1) in a D2O solution has shown that His41. has a pK(a) of 9.4, consistent with the NMR and X-ray structures at acidic to neutral pH, in which two imidazole nitrogen atoms of cationic His41 are hydrogen bonded to the main chain C=O groups of Thr37 and His118. Upon deprotonation of His41 at pH 9.4, the Thr37-His41-His118 hydrogen bond bridge breaks on the His118 side and SOD loses 70% of its activity. Concomitantly, hydrogen-deuterium exchange is accelerated for amide groups of beta-strands, indicating an increased conformational fluctuation of the beta-barrel. Thr37 and His41 are in direct contact with Leu36, whose hydrophobic side chain closes off the opening of the beta-barrel, while His118 is indirectly connected to Arg141 that assists the docking of superoxide to Cu. These Raman findings strongly suggest that the His41-mediated hydrogen bond bridge plays a crucial role in keeping the protein structure suitable for highly efficient catalytic reactions. The catalytic and structural role of His41 is consistent with the observation that the mutation of His43 in human SOD (equivalent to His41 in bovine SOD) to Arg largely reduces the dismutase activity and the protein structural stability.

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  • Catalytic and structural role of a metal-free histidine residue in bovine Cu-Zn superoxide dismutase

    A Toyama, Y Takahashi, H Takeuchi

    BIOCHEMISTRY   43 ( 16 )   4670 - 4679   2004年4月

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    記述言語:英語   出版者・発行元:AMER CHEMICAL SOC  

    Cu-Zn superoxide dismutase (SOD) contains a conserved, metal-free His residue at an opening of the backbone beta-barrel in addition to six Cu- and/or Zn-bound His residues in the active site. We examined the protonation and hydrogen bonding state of the metal-free His residue (His41) in bovine SOD by UV Raman spectroscopy. Analysis of the His Raman intensity at 1406 cm(-1) in a D2O solution has shown that His41. has a pK(a) of 9.4, consistent with the NMR and X-ray structures at acidic to neutral pH, in which two imidazole nitrogen atoms of cationic His41 are hydrogen bonded to the main chain C=O groups of Thr37 and His118. Upon deprotonation of His41 at pH 9.4, the Thr37-His41-His118 hydrogen bond bridge breaks on the His118 side and SOD loses 70% of its activity. Concomitantly, hydrogen-deuterium exchange is accelerated for amide groups of beta-strands, indicating an increased conformational fluctuation of the beta-barrel. Thr37 and His41 are in direct contact with Leu36, whose hydrophobic side chain closes off the opening of the beta-barrel, while His118 is indirectly connected to Arg141 that assists the docking of superoxide to Cu. These Raman findings strongly suggest that the His41-mediated hydrogen bond bridge plays a crucial role in keeping the protein structure suitable for highly efficient catalytic reactions. The catalytic and structural role of His41 is consistent with the observation that the mutation of His43 in human SOD (equivalent to His41 in bovine SOD) to Arg largely reduces the dismutase activity and the protein structural stability.

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  • Ca2+ binding sites in calmodulin and troponin C alter interhelical angle movements

    K Goto, A Toyama, H Takeuchi, K Takayama, T Saito, M Iwamoto, JZ Yeh, T Narahashi

    FEBS LETTERS   561 ( 1-3 )   51 - 57   2004年3月

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    記述言語:英語   出版者・発行元:ELSEVIER SCIENCE BV  

    Molecular dynamics analyses were performed to examine conformational changes in the C-domain of calmodulin and the N-domain of troponin C induced by binding of Ca2+ ions. Analyses of conformational changes in calmodulin and troponin C indicated that the shortening of the distance between Ca2+ ions and Ca2+ binding sites of helices caused widening of the distance between Ca2+ binding sites of helices on opposite sides, while the hydrophobic side chains in the center of helices hardly moved due to their steric hindrance. This conformational change acts as the clothespin mechanism. (C) 2004 Published by Elsevier B.V. on behalf of the Federation of European Biochemical Societies.

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  • Ca2+ binding sites in calmodulin and troponin C alter interhelical angle movements 国際誌

    K Goto, A Toyama, H Takeuchi, K Takayama, T Saito, M Iwamoto, JZ Yeh, T Narahashi

    FEBS LETTERS   561 ( 1-3 )   51 - 57   2004年3月

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    記述言語:英語   出版者・発行元:ELSEVIER SCIENCE BV  

    Molecular dynamics analyses were performed to examine conformational changes in the C-domain of calmodulin and the N-domain of troponin C induced by binding of Ca2+ ions. Analyses of conformational changes in calmodulin and troponin C indicated that the shortening of the distance between Ca2+ ions and Ca2+ binding sites of helices caused widening of the distance between Ca2+ binding sites of helices on opposite sides, while the hydrophobic side chains in the center of helices hardly moved due to their steric hindrance. This conformational change acts as the clothespin mechanism. (C) 2004 Published by Elsevier B.V. on behalf of the Federation of European Biochemical Societies.

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  • Assignments and hydrogen bond sensitivities of UV resonance Raman bands of the C8-deuterated guanine ring

    A Toyama, N Fujimoto, N Hanada, J Ono, E Yoshimitsu, A Matsubuchi, H Takeuchi

    JOURNAL OF RAMAN SPECTROSCOPY   33 ( 9 )   699 - 708   2002年9月

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    記述言語:英語   出版者・発行元:JOHN WILEY & SONS LTD  

    Isotope-edited Raman spectroscopy, a combination of site-selective isotopic labeling and Raman difference spectroscopy, is a useful method for studying the structure and interaction of individual nucleic acid residues in oligonucleotides. To obtain basic data for applying isotope-edited Raman spectroscopy to guanine residues, we studied the vibrational modes of UV resonance Raman bands of the C8-deuterated guanine ring by examining the wavenumber shifts upon seven isotopic substitutions (2-C-13, 2-N-15, 6-O-18, 7-N-15 8-C-13, 9-N-15 and 1'-C-13). The hydrogen bond sensitivities of the Raman bands were also investigated by comparing the Raman spectra recorded in several solvents of different hydrogen bonding properties. Some of the Raman bands were found to be markers of hydrogen bonding at specific donor or acceptor sites on the guanine ring. The Raman bands, which shift on C8-deuteration, remain in the difference spectrum between the unlabeled and C8-deuterated guanine rings. Among them, a negative peak around 1525 cm(-1) and a strong positive/negative peak pair around 1485/1465 cm(-1) serve as markers of hydrogen bonding at N7 and C6=O, respectively. Another weak positive/negative peak pair around 1025/1040 cm(-1) is sensitive to hydrogen bonding at the proton donor sites (N1-H and N2-H-2). The applicability of the hydrogen bond markers has been tested by using a 22-mer oligonucleotide duplex containing eight guanine residues and its analog in which a single guanine residue is C8-deuterated. The difference spectrum shows that the hydrogen bonding state of the guanine residue at the labeled position is consistent with the Watson-Crick base pair structure of DNA. Isotope-edited Raman spectroscopy is a useful tool for studying the hydrogen bonding state of selected guanine residues in oligonucleotides. Copyright (C) 2002 John Wiley Sons, Ltd.

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  • Assignments and hydrogen bond sensitivities of UV resonance Raman bands of the C8-deuterated guanine ring

    A Toyama, N Fujimoto, N Hanada, J Ono, E Yoshimitsu, A Matsubuchi, H Takeuchi

    JOURNAL OF RAMAN SPECTROSCOPY   33 ( 9 )   699 - 708   2002年9月

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    記述言語:英語   出版者・発行元:JOHN WILEY & SONS LTD  

    Isotope-edited Raman spectroscopy, a combination of site-selective isotopic labeling and Raman difference spectroscopy, is a useful method for studying the structure and interaction of individual nucleic acid residues in oligonucleotides. To obtain basic data for applying isotope-edited Raman spectroscopy to guanine residues, we studied the vibrational modes of UV resonance Raman bands of the C8-deuterated guanine ring by examining the wavenumber shifts upon seven isotopic substitutions (2-C-13, 2-N-15, 6-O-18, 7-N-15 8-C-13, 9-N-15 and 1'-C-13). The hydrogen bond sensitivities of the Raman bands were also investigated by comparing the Raman spectra recorded in several solvents of different hydrogen bonding properties. Some of the Raman bands were found to be markers of hydrogen bonding at specific donor or acceptor sites on the guanine ring. The Raman bands, which shift on C8-deuteration, remain in the difference spectrum between the unlabeled and C8-deuterated guanine rings. Among them, a negative peak around 1525 cm(-1) and a strong positive/negative peak pair around 1485/1465 cm(-1) serve as markers of hydrogen bonding at N7 and C6=O, respectively. Another weak positive/negative peak pair around 1025/1040 cm(-1) is sensitive to hydrogen bonding at the proton donor sites (N1-H and N2-H-2). The applicability of the hydrogen bond markers has been tested by using a 22-mer oligonucleotide duplex containing eight guanine residues and its analog in which a single guanine residue is C8-deuterated. The difference spectrum shows that the hydrogen bonding state of the guanine residue at the labeled position is consistent with the Watson-Crick base pair structure of DNA. Isotope-edited Raman spectroscopy is a useful tool for studying the hydrogen bonding state of selected guanine residues in oligonucleotides. Copyright (C) 2002 John Wiley Sons, Ltd.

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  • Raman spectra and normal coordinate analysis of the N1-H and N3-H tautomers of 4-methylimidazole: Vibrational modes of histidine tautomer markers

    A Toyama, K Ono, S Hashimoto, H Takeuchi

    JOURNAL OF PHYSICAL CHEMISTRY A   106 ( 14 )   3403 - 3412   2002年4月

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    記述言語:英語   出版者・発行元:AMER CHEMICAL SOC  

    The imidazole ring of histidine exists in two tautomeric forms in neutral-to-basic aqueous solution, and the tautomerism of the histidine residue sometimes plays a key role in catalytic reactions of enzymes. We have investigated the molecular vibrations of two tautomers of 4-methylimidazole (4-Melm), a model compound for the histidine side chain, by Raman spectroscopy and ab initio calculations based on the density functional theory (DFT) approach. Examination of the temperature dependence of Raman intensity revealed nine pairs of bands characteristic of the N1-protonated and the N3-protonated tautomers of 4-Melm at 1576/1596, 1452/1427, 1304/1344, 1265/1259, 1229/1234, 1165/1149, 1088/1104, 996/1014, and 942/934 cm(-1). Five to six pairs of tautomerism-sensitive Raman bands were also identified for each of the C2-, N-, and C2,N-deuterated analogues of 4-Melm. The observed Raman wavenumbers were used to determine nine scaling factors for the in-plane force constants derived from DFT calculations using the 6-311+G(2d, p) basis set. The force field finally obtained reproduces the experimental vibrational wavenumbers of four additional isotopomers (C5-, C5,N-, C2,C5-, and C2,C5,N-deuterated 4-Melm) as well. The vibrational modes calculated for 4-Melm are useful in understanding the origins of the previously proposed tautomer marker bands of histidine at 1568/1585, 1282/1260, 1090/1105, and 983/1004 cm(-1). A pair of Raman bands at 1320/1354 cm(-1) is suggested to be a new tautomer marker of histidine.

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  • Raman spectra and normal coordinate analysis of the N1-H and N3-H tautomers of 4-methylimidazole: Vibrational modes of histidine tautomer markers

    A Toyama, K Ono, S Hashimoto, H Takeuchi

    JOURNAL OF PHYSICAL CHEMISTRY A   106 ( 14 )   3403 - 3412   2002年4月

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    記述言語:英語   出版者・発行元:AMER CHEMICAL SOC  

    The imidazole ring of histidine exists in two tautomeric forms in neutral-to-basic aqueous solution, and the tautomerism of the histidine residue sometimes plays a key role in catalytic reactions of enzymes. We have investigated the molecular vibrations of two tautomers of 4-methylimidazole (4-Melm), a model compound for the histidine side chain, by Raman spectroscopy and ab initio calculations based on the density functional theory (DFT) approach. Examination of the temperature dependence of Raman intensity revealed nine pairs of bands characteristic of the N1-protonated and the N3-protonated tautomers of 4-Melm at 1576/1596, 1452/1427, 1304/1344, 1265/1259, 1229/1234, 1165/1149, 1088/1104, 996/1014, and 942/934 cm(-1). Five to six pairs of tautomerism-sensitive Raman bands were also identified for each of the C2-, N-, and C2,N-deuterated analogues of 4-Melm. The observed Raman wavenumbers were used to determine nine scaling factors for the in-plane force constants derived from DFT calculations using the 6-311+G(2d, p) basis set. The force field finally obtained reproduces the experimental vibrational wavenumbers of four additional isotopomers (C5-, C5,N-, C2,C5-, and C2,C5,N-deuterated 4-Melm) as well. The vibrational modes calculated for 4-Melm are useful in understanding the origins of the previously proposed tautomer marker bands of histidine at 1568/1585, 1282/1260, 1090/1105, and 983/1004 cm(-1). A pair of Raman bands at 1320/1354 cm(-1) is suggested to be a new tautomer marker of histidine.

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  • The alpha/beta barrel proteins oscillating energetically with large conformational changes in the presence of oxygen molecules.

    K Goto, A Toyama, K Takayama, Ueda, I, M Iwamoto, JZ Yeh, T Narahashi

    BIOPHYSICAL JOURNAL   82 ( 1 )   134A - 134A   2002年1月

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    記述言語:英語   掲載種別:研究発表ペーパー・要旨(国際会議)   出版者・発行元:BIOPHYSICAL SOCIETY  

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  • Binding modes of cyclic AMP and environments of tryptophan residues in 1 : 1 and 1 : 2 complexes of cyclic AMP receptor protein and cyclic AMP

    N Fujimoto, A Toyama, H Takeuchi

    BIOPOLYMERS   67 ( 3 )   186 - 196   2002年

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    記述言語:英語   出版者・発行元:JOHN WILEY & SONS INC  

    Cyclic AMP (cAMP) receptor protein (CRP) forms 1:1 and 1:2 complexes with cAMP, and the former complex is considered to be the most active form of CRP in binding to specific DNA sequences and in modulating gene transcription by RNA polymerases. We examine the cAMP binding modes and structural changes of CRP upon cAMP binding by UV resonance Raman spectroscopy. The Raman spectra of CRP-(cAMP)(1) and CRP-(cAMP)(2) extracted from those of CRP- cAMP mixtures at varied mixing ratios clearly show that the hydrogen bonding state and the conformation of cAMP in both complexes in solution are very similar to those found in the X-ray crystal structure of CRP-(cAMP)(2), which is evidence that the cAMP binding mode does not differ between the two complexes. The environmental hydrophobicity of Trp85 monitored by UV resonance Raman intensity shows a significant decrease upon binding of the first cAMP molecule, whereas no further change occurs in the second cAMP binding step. The environmental change of Trp85 suggests an opening of the cleft between the N-terminal cAMP and C-terminal DNA binding domains in the process of CRP activation by binding of a single cAMP molecule. (C) 2002 Wiley Periodicals, Inc.

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  • Binding modes of cyclic AMP and environments of tryptophan residues in 1 : 1 and 1 : 2 complexes of cyclic AMP receptor protein and cyclic AMP 国際誌

    N Fujimoto, A Toyama, H Takeuchi

    BIOPOLYMERS   67 ( 3 )   186 - 196   2002年

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    記述言語:英語   出版者・発行元:JOHN WILEY & SONS INC  

    Cyclic AMP (cAMP) receptor protein (CRP) forms 1:1 and 1:2 complexes with cAMP, and the former complex is considered to be the most active form of CRP in binding to specific DNA sequences and in modulating gene transcription by RNA polymerases. We examine the cAMP binding modes and structural changes of CRP upon cAMP binding by UV resonance Raman spectroscopy. The Raman spectra of CRP-(cAMP)(1) and CRP-(cAMP)(2) extracted from those of CRP- cAMP mixtures at varied mixing ratios clearly show that the hydrogen bonding state and the conformation of cAMP in both complexes in solution are very similar to those found in the X-ray crystal structure of CRP-(cAMP)(2), which is evidence that the cAMP binding mode does not differ between the two complexes. The environmental hydrophobicity of Trp85 monitored by UV resonance Raman intensity shows a significant decrease upon binding of the first cAMP molecule, whereas no further change occurs in the second cAMP binding step. The environmental change of Trp85 suggests an opening of the cleft between the N-terminal cAMP and C-terminal DNA binding domains in the process of CRP activation by binding of a single cAMP molecule. (C) 2002 Wiley Periodicals, Inc.

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  • Characterization of individual adenine residues in DNA by a combination of site-selective C8-deuteration and UV resonance Raman difference spectroscopy

    A Toyama, Y Miyagawa, A Yoshimura, N Fujimoto, H Takeuchi

    JOURNAL OF MOLECULAR STRUCTURE   598 ( 1 )   85 - 91   2001年10月

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    記述言語:英語   出版者・発行元:ELSEVIER SCIENCE BV  

    Raman spectroscopy has been combined with site-selective isotopic labeling techniques to obtain structural information on a selected nucleic acid residue in oligonucleotides. In the difference spectrum between the unlabeled and site-selectively labeled oligonucleotides, the Raman signals from the residue at the labeled position show up, while the signals from the residues at unlabeled positions are canceled out. To demonstrate the utility of this new method, we have prepared a self-complementary tetradecamer DNA, d(AGTGCTCGAGCACT)(2), containing single C8-deuterated adenine at position 9 (A9) or 12 (A12). UV (257 nm) resonance Raman difference spectra between the unlabeled and labeled oligonucleotides in solution reveal slightly different microenvironments around A9 and A 12 as expected for a double-stranded helical structure of the tetradecamer DNA. In the presence of an antitumor antibiotic, actinomycin D, which intercalates into the 5'-GC-3' sequence of DNA, the Raman signals of A9 on the 5'-side of the intercalation site become significantly weaker, indicating an increased base stacking with adjacent guanine bases. In contrast, the Raman signals of A12 on the 3'-side are not affected by the binding of actinomycin D. This observation provides the first experimental evidence that the intercalation of actinomycin D induces an asymmetric structural alteration of DNA in solution. (C) 2001 Elsevier Science B.V. All rights reserved.

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  • Characterization of individual adenine residues in DNA by a combination of site-selective C8-deuteration and UV resonance Raman difference spectroscopy

    A Toyama, Y Miyagawa, A Yoshimura, N Fujimoto, H Takeuchi

    JOURNAL OF MOLECULAR STRUCTURE   598 ( 1 )   85 - 91   2001年10月

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    記述言語:英語   出版者・発行元:ELSEVIER SCIENCE BV  

    Raman spectroscopy has been combined with site-selective isotopic labeling techniques to obtain structural information on a selected nucleic acid residue in oligonucleotides. In the difference spectrum between the unlabeled and site-selectively labeled oligonucleotides, the Raman signals from the residue at the labeled position show up, while the signals from the residues at unlabeled positions are canceled out. To demonstrate the utility of this new method, we have prepared a self-complementary tetradecamer DNA, d(AGTGCTCGAGCACT)(2), containing single C8-deuterated adenine at position 9 (A9) or 12 (A12). UV (257 nm) resonance Raman difference spectra between the unlabeled and labeled oligonucleotides in solution reveal slightly different microenvironments around A9 and A 12 as expected for a double-stranded helical structure of the tetradecamer DNA. In the presence of an antitumor antibiotic, actinomycin D, which intercalates into the 5'-GC-3' sequence of DNA, the Raman signals of A9 on the 5'-side of the intercalation site become significantly weaker, indicating an increased base stacking with adjacent guanine bases. In contrast, the Raman signals of A12 on the 3'-side are not affected by the binding of actinomycin D. This observation provides the first experimental evidence that the intercalation of actinomycin D induces an asymmetric structural alteration of DNA in solution. (C) 2001 Elsevier Science B.V. All rights reserved.

    DOI: 10.1016/S0022-2860(01)00808-0

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  • The Rotating Model : The α/β Barrel of the Bacterial Luciferase Stabilized Move Than the Crystal Structure with Large Simultaneous Conformational Changes

    Progress in Anesthetic Mechanism   6   568   2000年

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  • The Rotating Model : The α/β Barrel of the Bacterial Luciferase Stabilized Move Than the Crystal Structure with Large Simultaneous Conformational Changes

    Progress in Anesthetic Mechanism   6   568   2000年

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  • Assignments of guanosine UV resonance Raman bands on the basis of C-13, N-15 and O-18 substitution effects

    A Toyama, N Hanada, J Ono, E Yoshimitsu, H Takeuchi

    JOURNAL OF RAMAN SPECTROSCOPY   30 ( 8 )   623 - 630   1999年8月

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    記述言語:英語   出版者・発行元:JOHN WILEY & SONS LTD  

    UV resonance Raman spectra of guanosine and its seven isotope-substituted analogs (2-C-13, 2-N-15 6-O-18, 7-N-15, 8-C-13, 9-N-15 and 1'-C-13) were measured with 257 mn excitation in H2O and D2O solutions, In-plane vibrations of the guanine ring were selectively enhanced in the UV resonance Raman spectra, and most Raman bands showed significant wavenumber shifts upon isotopic substitution. The observed isotope shifts were used to assign the Raman bands to vibrations of the peripheral sites (N1-H, C2-NH2 and C6=O), the pyrimidine ring and/or the imidazole ring. Previous assignments for some Raman bands were shown to be inconsistent with the isotopic data and they were revised. Relationships between the vibrational modes and the sensitivities to hydrogen bonding or conformation are discussed for known Raman marker bands. Each hydrogen bond marker arises from a vibration that involves, at least partly, the proton donor or acceptor atom, All the marker bands of glycosidic bond orientation and ribose ring puckering actually involve atomic displacements around the N9-C1' moiety connecting the guanine ring to ribose, permitting vibrational coupling between them. The isotopic wavenumber shifts reported here may be useful in improving the force field for the 9-substituted guanine ring and in interpreting the vibrational spectra of guanine nucleoside and nucleotides. Copyright (C) 1999 John Wiley & Sons, Ltd.

    DOI: 10.1002/(SICI)1097-4555(199908)30:8<623::AID-JRS407>3.0.CO;2-9

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  • Assignments of guanosine UV resonance Raman bands on the basis of C-13, N-15 and O-18 substitution effects

    A Toyama, N Hanada, J Ono, E Yoshimitsu, H Takeuchi

    JOURNAL OF RAMAN SPECTROSCOPY   30 ( 8 )   623 - 630   1999年8月

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    記述言語:英語   出版者・発行元:JOHN WILEY & SONS LTD  

    UV resonance Raman spectra of guanosine and its seven isotope-substituted analogs (2-C-13, 2-N-15 6-O-18, 7-N-15, 8-C-13, 9-N-15 and 1'-C-13) were measured with 257 mn excitation in H2O and D2O solutions, In-plane vibrations of the guanine ring were selectively enhanced in the UV resonance Raman spectra, and most Raman bands showed significant wavenumber shifts upon isotopic substitution. The observed isotope shifts were used to assign the Raman bands to vibrations of the peripheral sites (N1-H, C2-NH2 and C6=O), the pyrimidine ring and/or the imidazole ring. Previous assignments for some Raman bands were shown to be inconsistent with the isotopic data and they were revised. Relationships between the vibrational modes and the sensitivities to hydrogen bonding or conformation are discussed for known Raman marker bands. Each hydrogen bond marker arises from a vibration that involves, at least partly, the proton donor or acceptor atom, All the marker bands of glycosidic bond orientation and ribose ring puckering actually involve atomic displacements around the N9-C1' moiety connecting the guanine ring to ribose, permitting vibrational coupling between them. The isotopic wavenumber shifts reported here may be useful in improving the force field for the 9-substituted guanine ring and in interpreting the vibrational spectra of guanine nucleoside and nucleotides. Copyright (C) 1999 John Wiley & Sons, Ltd.

    DOI: 10.1002/(SICI)1097-4555(199908)30:8<623::AID-JRS407>3.0.CO;2-9

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  • Effects of hydrogen bonding on the UV resonance Raman bands of the adenine ring and its C8-deuterated analog

    N Fujimoto, A Toyama, H Takeuchi

    JOURNAL OF MOLECULAR STRUCTURE   447 ( 1-2 )   61 - 69   1998年6月

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    記述言語:英語   出版者・発行元:ELSEVIER SCIENCE BV  

    Ultraviolet (UV) resonance Raman spectra of an acetyl derivative of adenosine and its C8-deuterated analog were measured in solvents with varied hydrogen bonding properties. The Raman spectrum of the acetyl derivative in H2O solution is almost identical to that of adenosine in H2O solution, indicating that the acetyl derivative is a good model for the adenine nucleotide in DNA, Most of the Raman bands increase or decrease in wavenumber upon hydrogen bonding at the proton-donor (C6-NH2) and proton-acceptor sites (N1, N3 and N7) of the adenine ring. Among them, the nu(1), nu(2), nu(3), nu(5) and nu(9) bands of the adenine ring and the nu(1)', nu(2)', nu(3)', nu(5)', nu(7)' and nu(9)' bands of the C8-deuterated adenine ring show wavenumber shifts larger than 5 cm(-1). Relative intensities of some Raman bands change as well. The wavenumber and intensity changes can be used as markers of hydrogen bonding at the proton donor and/or acceptor sites of the adenine ring. The Raman spectral difference between the nondeuterated and C8-D labeled adenine rings reflects the hydrogen-bonding state very sensitively and is expected to be useful in studying the hydrogen-bonding state of a particular adenine residue in oligonucleotides by a combination of site-selective C8-D labeling and UV resonance Raman spectroscopy. (C) 1998 Elsevier Science B.V. All rights reserved.

    DOI: 10.1016/S0022-2860(98)00301-9

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  • Effects of hydrogen bonding on the UV resonance Raman bands of the adenine ring and its C8-deuterated analog

    N Fujimoto, A Toyama, H Takeuchi

    JOURNAL OF MOLECULAR STRUCTURE   447 ( 1-2 )   61 - 69   1998年6月

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    記述言語:英語   出版者・発行元:ELSEVIER SCIENCE BV  

    Ultraviolet (UV) resonance Raman spectra of an acetyl derivative of adenosine and its C8-deuterated analog were measured in solvents with varied hydrogen bonding properties. The Raman spectrum of the acetyl derivative in H2O solution is almost identical to that of adenosine in H2O solution, indicating that the acetyl derivative is a good model for the adenine nucleotide in DNA, Most of the Raman bands increase or decrease in wavenumber upon hydrogen bonding at the proton-donor (C6-NH2) and proton-acceptor sites (N1, N3 and N7) of the adenine ring. Among them, the nu(1), nu(2), nu(3), nu(5) and nu(9) bands of the adenine ring and the nu(1)', nu(2)', nu(3)', nu(5)', nu(7)' and nu(9)' bands of the C8-deuterated adenine ring show wavenumber shifts larger than 5 cm(-1). Relative intensities of some Raman bands change as well. The wavenumber and intensity changes can be used as markers of hydrogen bonding at the proton donor and/or acceptor sites of the adenine ring. The Raman spectral difference between the nondeuterated and C8-D labeled adenine rings reflects the hydrogen-bonding state very sensitively and is expected to be useful in studying the hydrogen-bonding state of a particular adenine residue in oligonucleotides by a combination of site-selective C8-D labeling and UV resonance Raman spectroscopy. (C) 1998 Elsevier Science B.V. All rights reserved.

    DOI: 10.1016/S0022-2860(98)00301-9

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  • Correlation between vibrational frequencies and hydrogen bonding states of the guanine ring studied by UV resonance Raman spectroscopy of 2'-deoxy-3',5'-bis(triisopropylsilyl)guanosine dissolved in various

    A Toyama, M Hamuara, H Takeuchi

    JOURNAL OF MOLECULAR STRUCTURE   379 ( 1 )   99 - 108   1996年6月

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    記述言語:英語   出版者・発行元:ELSEVIER SCIENCE BV  

    Ultraviolet resonance Raman spectra of 2'-deoxy-3',5'-bis(triisopropylsilyl)guanosine (TPS-dGuo) were recorded in non-hydrogen bonding, proton acceptor, and proton donor/acceptor solvents. Raman spectral changes observed on going from inert to proton acceptor solvents were ascribed to the hydrogen bonding at the proton donor sites of the guanine ring(N1-H and C2-NH2), and the spectral changes associated with the solvent change from proton acceptor to donor/acceptor were ascribed to the hydrogen bonding at the proton acceptor sites (N3, C6=0, and N7). A Raman band appearing at 1624 cm(-1) in inert solvents is assigned mainly to the NH2 scissors mode and its frequency changes to approximate to 1640 cm(-1) in acceptor solvents, reflecting the hydrogen bonding at C2-NH2. Another band at 1581 cm(-1), arising largely from the N1-H bend, shows an upshift of approximate to 10 cm(-1) upon hydrogen bonding at either N1-H or acceptor sites. Hydrogen bonding at the acceptor sites also produces frequency shifts of other Raman bands (at 1710, 1565, 1528, 1481, and 1154 cm(-1) in 1,2-dichloroethane solution). Among the Raman bands listed above, the 1710 cm(-1) band due to the C6=0 stretch decreases in frequency, whereas the others increase. The downshift of the C6=0 stretching frequency is correlated with the strength of hydrogen bonding at C6=O. The frequency of the 1481 cm(-1) band increases with a decrease of the C6=O stretching frequency, indicating that the 1481 cm(-1) band is also a marker of hydrogen bonding at C6=O. This finding is in sharp contrast to the previously proposed correlation with the hydrogen bonding at N7. The 1565 cm(-1) band is assigned to a vibration mainly involving the N1-C2=N3 linkage, and its frequency increases with increasing strength of the hydrogen bond at N3. Three bands around 1315, 1 180, and 1030 cm(-1), which are known to be sensitive to the ribose ring puckering and glycosidic bond orientation, also show small frequency changes upon hydrogen bonding. The Raman marker bands for the hydrogen bonds at C2-NH2, N1-H, C6=0, and N3 are expected to be useful in studying the structures of nucleic acids and nucleic acid-protein complexes containing guanine residues.

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  • Correlation between vibrational frequencies and hydrogen bonding states of the guanine ring studied by UV resonance Raman spectroscopy of 2'-deoxy-3',5'-bis(triisopropylsilyl)guanosine dissolved in various

    A Toyama, M Hamuara, H Takeuchi

    JOURNAL OF MOLECULAR STRUCTURE   379 ( 1 )   99 - 108   1996年6月

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    記述言語:英語   出版者・発行元:ELSEVIER SCIENCE BV  

    Ultraviolet resonance Raman spectra of 2'-deoxy-3',5'-bis(triisopropylsilyl)guanosine (TPS-dGuo) were recorded in non-hydrogen bonding, proton acceptor, and proton donor/acceptor solvents. Raman spectral changes observed on going from inert to proton acceptor solvents were ascribed to the hydrogen bonding at the proton donor sites of the guanine ring(N1-H and C2-NH2), and the spectral changes associated with the solvent change from proton acceptor to donor/acceptor were ascribed to the hydrogen bonding at the proton acceptor sites (N3, C6=0, and N7). A Raman band appearing at 1624 cm(-1) in inert solvents is assigned mainly to the NH2 scissors mode and its frequency changes to approximate to 1640 cm(-1) in acceptor solvents, reflecting the hydrogen bonding at C2-NH2. Another band at 1581 cm(-1), arising largely from the N1-H bend, shows an upshift of approximate to 10 cm(-1) upon hydrogen bonding at either N1-H or acceptor sites. Hydrogen bonding at the acceptor sites also produces frequency shifts of other Raman bands (at 1710, 1565, 1528, 1481, and 1154 cm(-1) in 1,2-dichloroethane solution). Among the Raman bands listed above, the 1710 cm(-1) band due to the C6=0 stretch decreases in frequency, whereas the others increase. The downshift of the C6=0 stretching frequency is correlated with the strength of hydrogen bonding at C6=O. The frequency of the 1481 cm(-1) band increases with a decrease of the C6=O stretching frequency, indicating that the 1481 cm(-1) band is also a marker of hydrogen bonding at C6=O. This finding is in sharp contrast to the previously proposed correlation with the hydrogen bonding at N7. The 1565 cm(-1) band is assigned to a vibration mainly involving the N1-C2=N3 linkage, and its frequency increases with increasing strength of the hydrogen bond at N3. Three bands around 1315, 1 180, and 1030 cm(-1), which are known to be sensitive to the ribose ring puckering and glycosidic bond orientation, also show small frequency changes upon hydrogen bonding. The Raman marker bands for the hydrogen bonds at C2-NH2, N1-H, C6=0, and N3 are expected to be useful in studying the structures of nucleic acids and nucleic acid-protein complexes containing guanine residues.

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  • ASSIGNMENT OF ADENINE RING INPLANE VIBRATIONS IN ADENOSINE ON THE BASIS OF N-15 AND C-13 ISOTOPIC FREQUENCY-SHIFTS AND UV RESONANCE RAMAN ENHANCEMENT

    A TOYAMA, N HANADA, Y ABE, H TAKEUCHI, HARADA, I

    JOURNAL OF RAMAN SPECTROSCOPY   25 ( 7-8 )   623 - 630   1994年7月

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    記述言語:英語   出版者・発行元:JOHN WILEY & SONS LTD  

    Infrared, Raman and UV resonance Raman spectra of adenosine and its 1,3-N-15(2), 2-C-13, and 8-C-13 isotopic analogues were measured in neutral aqueous solution (Raman and UV Raman) and in the crystalline state (infrared and Raman). The observed isotopic wavenumber shifts are useful in distinguishing adenine ring vibrations from ribose vibrations. In-plane modes of the adenine ring are selectively enhanced in UV resonance Raman spectra, which facilitates the assignment of the in-plane vibrations. In addition to the in-plane modes, a ribose vibration coupled with adenine in-plane vibrations was identified in the UV resonance Raman spectra. The fundamental wavenumbers for 22 in-plane normal modes of the 9-substituted adenine ring of adenosine in the 1700-250 cm-1 region are proposed. Although the fundamental wavenumbers of adenosine correspond well with those of adenine above 1350 cm-1 and below 800 cm-1, the vibrations in the 1350-800 cm-1 region are appreciably affected by the presence of the N-9-C-1' glycosidic bond and the couplings between ribose and adenine ring vibrational motions. The adenosine fundamental wavenumbers and their isotopic shifts reported here may be useful in analysing vibrational spectra of adenine nucleosides and nucleotides and in improving the force field of the 9-substituted adenine ring.

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  • ASSIGNMENT OF ADENINE RING INPLANE VIBRATIONS IN ADENOSINE ON THE BASIS OF N-15 AND C-13 ISOTOPIC FREQUENCY-SHIFTS AND UV RESONANCE RAMAN ENHANCEMENT

    A TOYAMA, N HANADA, Y ABE, H TAKEUCHI, HARADA, I

    JOURNAL OF RAMAN SPECTROSCOPY   25 ( 7-8 )   623 - 630   1994年7月

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    記述言語:英語   出版者・発行元:JOHN WILEY & SONS LTD  

    Infrared, Raman and UV resonance Raman spectra of adenosine and its 1,3-N-15(2), 2-C-13, and 8-C-13 isotopic analogues were measured in neutral aqueous solution (Raman and UV Raman) and in the crystalline state (infrared and Raman). The observed isotopic wavenumber shifts are useful in distinguishing adenine ring vibrations from ribose vibrations. In-plane modes of the adenine ring are selectively enhanced in UV resonance Raman spectra, which facilitates the assignment of the in-plane vibrations. In addition to the in-plane modes, a ribose vibration coupled with adenine in-plane vibrations was identified in the UV resonance Raman spectra. The fundamental wavenumbers for 22 in-plane normal modes of the 9-substituted adenine ring of adenosine in the 1700-250 cm-1 region are proposed. Although the fundamental wavenumbers of adenosine correspond well with those of adenine above 1350 cm-1 and below 800 cm-1, the vibrations in the 1350-800 cm-1 region are appreciably affected by the presence of the N-9-C-1' glycosidic bond and the couplings between ribose and adenine ring vibrational motions. The adenosine fundamental wavenumbers and their isotopic shifts reported here may be useful in analysing vibrational spectra of adenine nucleosides and nucleotides and in improving the force field of the 9-substituted adenine ring.

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  • ULTRAVIOLET RESONANCE RAMAN-SPECTRA OF RIBOSYL C(1')-DEUTERATED PURINE NUCLEOSIDES - EVIDENCE OF VIBRATIONAL COUPLING BETWEEN PURINE AND RIBOSE RINGS

    A TOYAMA, Y TAKINO, H TAKEUCHI, HARADA, I

    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY   115 ( 24 )   11092 - 11098   1993年12月

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    記述言語:英語   出版者・発行元:AMER CHEMICAL SOC  

    Ultraviolet resonance Raman spectra of ribosyl C(1')-deuterated guanosine and adenosine were measured. Most in-plane vibrations of the purine rings in the 1420-1100-cm-1 region showed frequency upshifts upon C(1')-deuteration, while those in the 1100-700-cm-1 region showed downshifts. The purine ring vibrations above 1450 cm-1 were unaffected. The frequency shifts associated with the C(1')-deuteration are explained by assuming couplings of the purine vibrations with a ribose C(1')-H bending mode, which involves a hydrogen motion in the plane of N(9)-C(1')-H. The purine vibrations that showed upshifts in the 1420-1100-cm-1 region are originally lowered in frequency by coupling with the ribosyl bending mode alpha(CH) around 1420 cm-1 and restore their intrinsic frequencies upon shifting of alpha(CH) to alpha(CD) around 1100 cm-1 in the C(1')-D isotopomers. Some of the upshifted vibrations may be further pushed up by coupling with alpha(CD). On the other hand, the downshifted purine modes in the 1100-700-cm-1 region do not interact with alpha(CH) because of large frequency separations from alpha(CH) and retain their intrinsic frequencies in the C(1')-H species. In the C(1')-D species, however, alpha(CD) couples with these modes and pushes their frequencies downward. The observed C(1')-D frequency shifts provide direct evidence of vibrational coupling between the base and ribose rings, suggesting that the purine base vibrations may be affected by the ribose ring puckering and glycosidic bond orientation. Actually, most of the purine vibrations that showed significant C(1')-D shifts are known or proved to be conformational markers of purine nucleosides and nucleotides. The conformational sensitivity of purine vibrations really arises from vibrational coupling between the base and ribose rings.

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  • ULTRAVIOLET RESONANCE RAMAN-SPECTRA OF RIBOSYL C(1')-DEUTERATED PURINE NUCLEOSIDES - EVIDENCE OF VIBRATIONAL COUPLING BETWEEN PURINE AND RIBOSE RINGS

    A TOYAMA, Y TAKINO, H TAKEUCHI, HARADA, I

    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY   115 ( 24 )   11092 - 11098   1993年12月

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    記述言語:英語   出版者・発行元:AMER CHEMICAL SOC  

    Ultraviolet resonance Raman spectra of ribosyl C(1')-deuterated guanosine and adenosine were measured. Most in-plane vibrations of the purine rings in the 1420-1100-cm-1 region showed frequency upshifts upon C(1')-deuteration, while those in the 1100-700-cm-1 region showed downshifts. The purine ring vibrations above 1450 cm-1 were unaffected. The frequency shifts associated with the C(1')-deuteration are explained by assuming couplings of the purine vibrations with a ribose C(1')-H bending mode, which involves a hydrogen motion in the plane of N(9)-C(1')-H. The purine vibrations that showed upshifts in the 1420-1100-cm-1 region are originally lowered in frequency by coupling with the ribosyl bending mode alpha(CH) around 1420 cm-1 and restore their intrinsic frequencies upon shifting of alpha(CH) to alpha(CD) around 1100 cm-1 in the C(1')-D isotopomers. Some of the upshifted vibrations may be further pushed up by coupling with alpha(CD). On the other hand, the downshifted purine modes in the 1100-700-cm-1 region do not interact with alpha(CH) because of large frequency separations from alpha(CH) and retain their intrinsic frequencies in the C(1')-H species. In the C(1')-D species, however, alpha(CD) couples with these modes and pushes their frequencies downward. The observed C(1')-D frequency shifts provide direct evidence of vibrational coupling between the base and ribose rings, suggesting that the purine base vibrations may be affected by the ribose ring puckering and glycosidic bond orientation. Actually, most of the purine vibrations that showed significant C(1')-D shifts are known or proved to be conformational markers of purine nucleosides and nucleotides. The conformational sensitivity of purine vibrations really arises from vibrational coupling between the base and ribose rings.

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  • INFRARED DICHROISM OF AN ELASTIC PORTION (1200 KDA FRAGMENT) OF CONNECTIN

    Y NAKAUCHI, A TOYAMA, HARADA, I, K MARUYAMA

    PROCEEDINGS OF THE JAPAN ACADEMY SERIES B-PHYSICAL AND BIOLOGICAL SCIENCES   69 ( 8 )   224 - 226   1993年10月

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    記述言語:英語   出版者・発行元:JAPAN ACAD  

    Infrared spectra of an oriented fiber made from 1200 kDa fragment of rabbit skeletal muscle connectin (titin) showed an abundance of beta-sheet structures. Infrared dichroism revealed that the beta-sheets were alligned with their mainchain axes parallel to the fibre axis. This conclusion is in good agreement with the results of chicken breast muscle beta-connectin (Uchida, K. et al., FEBS Lett., 295, 35-38 (1991)). A model of molecular structure of connectin is presented.

    DOI: 10.2183/pjab.69.224

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  • INFRARED DICHROISM OF AN ELASTIC PORTION (1200 KDA FRAGMENT) OF CONNECTIN

    Y NAKAUCHI, A TOYAMA, HARADA, I, K MARUYAMA

    PROCEEDINGS OF THE JAPAN ACADEMY SERIES B-PHYSICAL AND BIOLOGICAL SCIENCES   69 ( 8 )   224 - 226   1993年10月

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    記述言語:英語   出版者・発行元:JAPAN ACAD  

    Infrared spectra of an oriented fiber made from 1200 kDa fragment of rabbit skeletal muscle connectin (titin) showed an abundance of beta-sheet structures. Infrared dichroism revealed that the beta-sheets were alligned with their mainchain axes parallel to the fibre axis. This conclusion is in good agreement with the results of chicken breast muscle beta-connectin (Uchida, K. et al., FEBS Lett., 295, 35-38 (1991)). A model of molecular structure of connectin is presented.

    DOI: 10.2183/pjab.69.224

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  • ULTRAVIOLET RESONANCE RAMAN-SPECTRA OF PHYTOCHROME - A COMPARISON OF THE ENVIRONMENTS OF TRYPTOPHAN SIDE-CHAINS BETWEEN RED-LIGHT ABSORBING AND FAR RED-LIGHT ABSORBING FORMS

    A TOYAMA, M NAKAZAWA, K MANABE, H TAKEUCHI, HARADA, I

    PHOTOCHEMISTRY AND PHOTOBIOLOGY   57 ( 2 )   391 - 395   1993年2月

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    記述言語:英語   掲載種別:記事・総説・解説・論説等(学術雑誌)   出版者・発行元:AMER SOC PHOTOBIOLOGY  

    Ultraviolet resonance Raman spectra of phytochrome in the red light-absorbing form (Pr) and the far-red light-absorbing form (Pfr) are reported. The spectra excited at 240-nm provide structural information about the protein part of phytochrome. The protein contains only a very small amount of beta-sheet structure and most of the tyrosine side chains are located in hydrophobic environments. Indole rings of tryptophan (Trp) interact with neighboring groups in the Pr form and these interactions become weaker with the conversion from Pr to Pfr. Some Trp side chains of Pfr are surrounded by aliphatic groups but such is not the case in Pr. These changes in the environment occur at the same time as changes in orientation of Trp side chains. Our observations suggest that interactions between Trp residues and the tetrapyrrolic chromophore occur in the Pr form and that the strength of these interactions diminishes in the Pfr form.

    DOI: 10.1111/j.1751-1097.1993.tb02307.x

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  • ULTRAVIOLET RESONANCE RAMAN-SPECTRA OF PHYTOCHROME - A COMPARISON OF THE ENVIRONMENTS OF TRYPTOPHAN SIDE-CHAINS BETWEEN RED-LIGHT ABSORBING AND FAR RED-LIGHT ABSORBING FORMS

    A TOYAMA, M NAKAZAWA, K MANABE, H TAKEUCHI, HARADA, I

    PHOTOCHEMISTRY AND PHOTOBIOLOGY   57 ( 2 )   391 - 395   1993年2月

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    記述言語:英語   掲載種別:記事・総説・解説・論説等(学術雑誌)   出版者・発行元:AMER SOC PHOTOBIOLOGY  

    Ultraviolet resonance Raman spectra of phytochrome in the red light-absorbing form (Pr) and the far-red light-absorbing form (Pfr) are reported. The spectra excited at 240-nm provide structural information about the protein part of phytochrome. The protein contains only a very small amount of beta-sheet structure and most of the tyrosine side chains are located in hydrophobic environments. Indole rings of tryptophan (Trp) interact with neighboring groups in the Pr form and these interactions become weaker with the conversion from Pr to Pfr. Some Trp side chains of Pfr are surrounded by aliphatic groups but such is not the case in Pr. These changes in the environment occur at the same time as changes in orientation of Trp side chains. Our observations suggest that interactions between Trp residues and the tetrapyrrolic chromophore occur in the Pr form and that the strength of these interactions diminishes in the Pfr form.

    DOI: 10.1111/j.1751-1097.1993.tb02307.x

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  • ULTRAVIOLET RESONANCE RAMAN-SPECTRA OF CYCLIC-AMP RECEPTOR PROTEIN - STRUCTURAL-CHANGE INDUCED BY CYCLIC-AMP BINDING AND THE CONFORMATION OF PROTEIN-BOUND CYCLIC-AMP

    A TOYAMA, E KURASHIKI, Y WATANABE, H TAKEUCHI, HARADA, I, H AIBA, BJ LEE, Y KYOGOKU

    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY   113 ( 9 )   3615 - 3616   1991年4月

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    記述言語:英語   掲載種別:記事・総説・解説・論説等(学術雑誌)   出版者・発行元:AMER CHEMICAL SOC  

    DOI: 10.1021/ja00009a071

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  • ULTRAVIOLET RESONANCE RAMAN-SPECTRA OF CYCLIC-AMP RECEPTOR PROTEIN - STRUCTURAL-CHANGE INDUCED BY CYCLIC-AMP BINDING AND THE CONFORMATION OF PROTEIN-BOUND CYCLIC-AMP

    A TOYAMA, E KURASHIKI, Y WATANABE, H TAKEUCHI, HARADA, I, H AIBA, BJ LEE, Y KYOGOKU

    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY   113 ( 9 )   3615 - 3616   1991年4月

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    記述言語:英語   掲載種別:記事・総説・解説・論説等(学術雑誌)   出版者・発行元:AMER CHEMICAL SOC  

    DOI: 10.1021/ja00009a071

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  • ULTRAVIOLET RESONANCE RAMAN-SPECTRA OF ADENINE, URACIL AND THYMINE DERIVATIVES IN SEVERAL SOLVENTS - CORRELATION BETWEEN BAND FREQUENCIES AND HYDROGEN-BONDING STATES OF THE NUCLEIC-ACID BASES

    A TOYAMA, H TAKEUCHI, HARADA, I

    JOURNAL OF MOLECULAR STRUCTURE   242 ( 1 )   87 - 98   1991年1月

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    記述言語:英語   出版者・発行元:ELSEVIER SCIENCE BV  

    Ultraviolet resonance Raman spectra (266-nm excitation) were studied for adenine, uracil and thymine derivatives in several solvents at low concentrations (0.5-10 mM) where hydrogen bonding between solute molecules is negligible. The Raman spectral patterns depend critically on the proton-accepting/donating properties of the solvents. Raman bands which show large solvent effects are expected to be useful in studying the hydrogen-bonding states of the nucleic acid bases.

    DOI: 10.1016/0022-2860(91)87129-6

    Web of Science

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  • ULTRAVIOLET RESONANCE RAMAN-SPECTRA OF ADENINE, URACIL AND THYMINE DERIVATIVES IN SEVERAL SOLVENTS - CORRELATION BETWEEN BAND FREQUENCIES AND HYDROGEN-BONDING STATES OF THE NUCLEIC-ACID BASES

    A TOYAMA, H TAKEUCHI, HARADA, I

    JOURNAL OF MOLECULAR STRUCTURE   242 ( 1 )   87 - 98   1991年1月

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    記述言語:英語   出版者・発行元:ELSEVIER SCIENCE BV  

    Ultraviolet resonance Raman spectra (266-nm excitation) were studied for adenine, uracil and thymine derivatives in several solvents at low concentrations (0.5-10 mM) where hydrogen bonding between solute molecules is negligible. The Raman spectral patterns depend critically on the proton-accepting/donating properties of the solvents. Raman bands which show large solvent effects are expected to be useful in studying the hydrogen-bonding states of the nucleic acid bases.

    DOI: 10.1016/0022-2860(91)87129-6

    Web of Science

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  • INTERACTIONS OF GUANINE DERIVATIVES WITH ETHYLENEDIAMINE AND DIETHYLENETRIAMINE COMPLEXES OF PALLADIUM(II) IN SOLUTION - PD BINDING-SITES OF THE GUANINE RING AND FORMATION OF A CYCLIC ADDUCT, [(PD(EN)(GUANINE RING))4]

    K UCHIDA, A TOYAMA, Y TAMURA, M SUGIMURA, F MITSUMORI, Y FURUKAWA, H TAKEUCHI, HARADA, I

    INORGANIC CHEMISTRY   28 ( 11 )   2067 - 2073   1989年5月

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    記述言語:英語   出版者・発行元:AMER CHEMICAL SOC  

    DOI: 10.1021/ic00310a012

    Web of Science

    CiNii Article

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  • INTERACTIONS OF GUANINE DERIVATIVES WITH ETHYLENEDIAMINE AND DIETHYLENETRIAMINE COMPLEXES OF PALLADIUM(II) IN SOLUTION - PD BINDING-SITES OF THE GUANINE RING AND FORMATION OF A CYCLIC ADDUCT, [(PD(EN)(GUANINE RING))4]

    K UCHIDA, A TOYAMA, Y TAMURA, M SUGIMURA, F MITSUMORI, Y FURUKAWA, H TAKEUCHI, HARADA, I

    INORGANIC CHEMISTRY   28 ( 11 )   2067 - 2073   1989年5月

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    記述言語:英語   出版者・発行元:AMER CHEMICAL SOC  

    DOI: 10.1021/ic00310a012

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共同研究・競争的資金等の研究

  • カチオン-π相互作用によるタンパク質のダイナミックな構造制御

    研究課題/領域番号:16350003

    2004年 - 2006年

    制度名:科学研究費助成事業

    研究種目:基盤研究(B)

    提供機関:日本学術振興会

    竹内 英夫, 三浦 隆史, 外山 聡

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    配分額:15900000円 ( 直接経費:15900000円 )

    正電荷とπ電子との間の相互作用、いわゆるカチオン-π相互作用が、タンパク質の構造形成と機能発現時の構造ダイナミックスに及ぼす影響を、円偏光二色性、蛍光、紫外共鳴ラマン散乱の各種分光法を用いて検討した。対象としたペプチドは、His^+-Trp間のカチオン-π相互作用を行なう可能性があるニューロメディンB、ニューロメディンC、および、B型インフルエンザウイルスのBM2タンパク質の膜貫通領域BM2-TMPである。その結果、カチオン-π相互作用は、ニューロメディンBやニューロメディンCの2次構造を制御できるほど強くはなく、構造形成への貢献は大きくないことが分かった。しかし、His^+-Trp間のカチオン-π相互作用が、脂質膜中に埋め込んだBM2-TMPの形成するプロトンチャネルの開閉を制御することが明らかになり、このことから、カチオン-π相互作用は、一旦形成された構造をわずか変化させ、タンパク質の機能発現を制御する過程においては、重要な役割を果たし得ると結論された。また、本研究の過程において、Cu^<2+>がTrp側鎖とカチオン-π相互作用を行う場合は、吸収スペクトルのシフトと強度変化だけでなく、CDスペクトルにも特徴的な負のシグナルが生じることも見出した。このCDシグナルは、Cu^<2+>とTrp側鎖の間のカチオン-π相互作用を検出するための新たなマーカーとして有用であると期待される。BM2-TMPが形成するイオンチャネルの場合に見られたように、カチオン-π相互作用がタンパク質の機能発現時の構造ダイナミックスに大きな影響を与えることは、他のタンパク質の場合も十分考えられる。今後、幅広い種類のタンパク質について、このことを検証する必要があるが、その手がかりが本研究で得られた。

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  • 選択的重水素化とラマン差スペクトル強度を利用した薬物結合時の核酸構造変化の検出

    研究課題/領域番号:15590036

    2003年 - 2004年

    制度名:科学研究費助成事業

    研究種目:基盤研究(C)

    提供機関:日本学術振興会

    外山 聡

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    配分額:3000000円 ( 直接経費:3000000円 )

    本研究の最終目標は、選択的同位元素ラベルと紫外共鳴ラマン(UVRR)分光を組み合わせた、"isotope-edited UVRR分光法"を用いて、薬物とDNAの相互作用のメカニズムを理解することである。本研究課題の目的は、DNA塩基の構造とUVRR強度の間の相関関係を見出すことにある。
    アデニン、グアニン誘導体のUVRRスペクトルをいくつかの溶媒中で測定した。UVRRバンド強度をKamlet-Taftの溶媒パラメータを用いて分析した。その結果、プリン環のラマン強度は、主に溶媒の水素結合供与能に依存することが解った。
    一方、塩基のスタッキング相互作用により塩基のラマン強度が小さくなることも良く知られている(ラマンの淡色効果)。スタッキングと水素結合のどちらがラマン強度において支配的であるかを決めるために、cAMP受容蛋白質(CRP)が結合した22-mer DNAのisotope-edited UVRRスペクトルを測定した。CRP-(cAMP)2複合体は、いくつかのグアニンと強く水素結合するが、これらグアニンのスタッキングはほとんど変化しないことが知られている。CRP-(cAMP)2複合体の結合に伴い、これらグアニンのラマンバンドに波数変化が起きたが、意味のある強度変化は見られなかった。この結果は、水溶液中のDNAについては、塩基のスタッキング相互作用の強さがUVRR強度を主に決定することを示している。塩基のスタッキングに対するisotope-edited UVRRスペクトルの鋭敏度を評価するため、ACミスマッチを含む19-merのスペクトルを測定した。DNAのpre-meltingの状態でも、ミスマッチ近傍の塩基のラマン強度の変化が検知できた。この結果は、isotope-edited UVRRスペクトルの強度変化が、スタッキング状態のプローブとして有用であることを示している。

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  • 重水素置換と共鳴ラマン分光法による生理的条件下の薬物結合に伴う核酸構造変化の検出

    研究課題/領域番号:13672248

    2001年 - 2002年

    制度名:科学研究費助成事業

    研究種目:基盤研究(C)

    提供機関:日本学術振興会

    外山 聡

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    配分額:3500000円 ( 直接経費:3500000円 )

    位置選択的同位元素置換と紫外共鳴ラマン差スペクトルを組み合わせた"Isotope-edited Raman spectroscopy"により、希薄水溶液中において、DNA中の選択した1塩基のグアニンの微細な構造変化を検出した。[8-D]グアニンでラベルしたオリゴヌクレオチドとラベルしていないオリゴヌクレオチドの251nm励起紫外共鳴ラマン(UVRR)スペクトルを測定した。未置換体とラベル体の差スペクトルを計算すると、ラベル化した位置の塩基のラマンシグナルは現れるが、他の部分は相殺する。したがって、オリゴヌクレオチド中の選択したグアニンのラマンシグナルが抽出できる。
    Isotope-edited Raman spectroscopyからグアニン塩基の構造解析を行うための基礎データとして、同位元素置換による振動数変化を元にしたC8重水素化グアニン環の振動モードを調べた。ラマンバンドの水素結合感受性を、水素結合能の異なる各種溶媒に溶解した時のラマンスペクトルの比較により調べた。この結果、いくつかのラマンバンドから、グアニン環のN1-HとC2-NH_2、C6=O、N7それぞれの水素結合部位の状態を調べられることが解った。
    オリゴヌクレオチド22merの2本鎖DNAを用いて、Isotope-edited Raman spectroscopyの有用性を確認した。2本鎖DNAのグアニン塩基と直接水素結合することが知られているcAMP受容タンパク質(CRP)の存在下、非存在下で、UVRRスペクトルを測定した。その結果、CRPはグアニンのC6=Oと水素結合し、N7とは水素結合しないことが解った。Isotope-edited Raman spectroscopyは、生理的条件下、核酸-薬物系における特定のグアニン残基の構造情報が得られる優れた方法と考えられる。

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  • 重水素置換と共鳴ラマン分光法を併用した薬物-DNAオリゴマ-相互作用の構造研究

    研究課題/領域番号:11771407

    1999年 - 2000年

    制度名:科学研究費助成事業

    研究種目:奨励研究(A)

    提供機関:日本学術振興会

    外山 聡

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    配分額:2100000円 ( 直接経費:2100000円 )

    本研究の目的は、共鳴ラマン分光法を用いて、DNA-薬物の相互作用様式を詳細に調べることである。ラマン分光法は、薬物が「どのように」結合するかという情報を与えるため、DNA-薬物の相互作用を調べる手段として有用である。しかし、ラマン分光法からは、薬物が「どこに」結合するか解らない。これを解決するために、昨年度開発した方法で合成した、1残基のみに重水素を導入したDNAオリゴマーを採用した。DNAオリゴマーと薬物の複合体のラマンスペクトルを、重水素化体と未置換体の双方について測定し、両者のスペクトルの差を計算する。この差スペクトルにおいては、重水素化されていない部分のスペクトルは相殺され、重水素化した残基のシグナルのみが残る。
    薬物としては、抗がん性抗生物質アクチノマイシンD(ActD)を用いた。DNAは、ActD結合部位を含む自己相補鎖d(AGTGCTCGA^9GCA^<12>CT)_2の、A^9またはA^<12>のみを重水素ラベルしたものを使用した(下線を付した部分にActDがインターカレートする)。DNAにActDが結合すると、A^9のラマンバンド強度は約40%減少したが、A^<12>のラマンバンドには有意な変化がなかった。A^9のラマンバンド強度減少の原因は、塩基のスタッキングが強まることによるラマン淡色効果である。この結果は、ActDの結合に伴うDNAの巻戻りが主に5'側のみに起こり、この巻戻りがA^9のスタッキングを増加させたことを示している。
    X線結晶解析によると、ActD結合に伴うDNAの構造変化には、結晶化の条件により、5'側が巻戻るもの、3'側が巻戻るもの、両側均等に巻戻る場合がある。本研究により、生理的条件では5'側のみに巻戻りが起こることを決定することができた。重水素置換と共鳴ラマン分光法を併用した本方法は、他の薬物のDNA結合様式の解明にも汎用できる、新規な方法であると考えている。

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  • 紫外共鳴ラマン分光法による蛋白質に結合したアデニンヌクレオチドの構造研究

    研究課題/領域番号:08740436

    1996年

    制度名:科学研究費助成事業

    研究種目:奨励研究(A)

    提供機関:日本学術振興会

    外山 聡

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    配分額:1100000円 ( 直接経費:1100000円 )

    本研究は、紫外共鳴ラマン分光を用いて、蛋白質(サイクリックAMP受容蛋白質(CRP)や乳酸脱水素酵素)と複合体を形成した状態のアデニンヌクレオチド(サイクリックAMP (cAMP)やNADH)の構造を明らかにすることである。これらヌクレオチドは蛋白質のアロステリックエフェクターとなっており、その構造を知ることは重要である。
    260nm励起光を用いることで,CRP-cAMP混合系において,cAMPに選択的な共鳴ラマンスペクトルを測定することができた。このスペクトルより,CRPに結合したcAMPについて,そのコンフォメーションとアデニン環の水素結合状態について詳細な知見が得られた。関連実験として,CRPに結合したcGMP (cAMPと同様にCRPに結合するが,CRPを活性化しない)の紫外共鳴ラマンスペクトルも測定した。これにより,CRPに結合したcGMPについても構造情報が得られた。CRPに結合したcAMPとcGMPの構造を比較することにより,アロステリックエフェクターの構造とCRPの活性にどのような関連があるかについて,議論することができた。
    一方,乳酸脱水素酵素に結合したNADHについては,蛍光の妨害により,260nm励起のスペクトルを測定することはできなかった。励起光を変化させる実験などを行ったが,現在のところ満足の行く結果は得られていない。
    本研究により,紫外共鳴ラマン分光法は,蛋白質に結合したヌクレオチドの構造を研究するのに優れた手段であることが明らかとなった。現在のところ,乳酸脱水素酵素のように本法を適用し難い蛋白質もあるが,測定法の改良などにより,紫外共鳴ラマン分光法は多くの蛋白質について,それに結合した核酸誘導体の構造を研究する手段になると期待される。

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  • 細胞構造解析用高性能紫外顕微ラマン分光システムの試作

    研究課題/領域番号:07554025

    1995年 - 1996年

    制度名:科学研究費助成事業

    研究種目:基盤研究(A)

    提供機関:日本学術振興会

    竹内 英夫, 外山 聡, 橋本 慎二, 三浦 隆史

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    配分額:15900000円 ( 直接経費:15900000円 )

    細胞内小器官の構造解析や特定生体成分の細胞内分布分析に応用できるだけの高感度・高分解能紫外顕微ラマン分光システムを試作するために、以下の技術的検討を行い、今後の改良の余地はいくつかあるものの、紫外顕微ラマン分光システムのプロトタイプを開発することができた。
    1.ラマン散乱励起用光源としては、試料に対する損傷を最小限に押さえるために、連続発振型紫外レーザーを採用した。このレーザーを種々の蛋白質や核酸などのラマンスペクトル測定に応用したところ、パルス発振型レーザーに比べて試料の損傷が格段に少なく、顕微測定用光源として最適であることを確認した。
    2.顕微照射・集光部に用いる対物レンズとしては、通常のレンズ型および反射鏡型の二種について、倍率、明るさ、収差、使用可能最短波長などを比較検討した結果、最短波長では反射鏡型の方が優れるが、他の点ではレンズ型の方が優れるため、レンズ型の対物レンズを採用した。また、ビームスプリッターは、種々の透過/反射比率のものを検討した結果、無蛍光性合成石英板が最適であることを見出した。
    3.光源部および顕微照射・集光部と現有の紫外ラマン分光器を組み合わせるための光学系を作製し、これらの部分を最適配置に組み合わせることにより、紫外顕微ラマン分光システムを試作した。
    4.試作器を用いて紫外顕微ラマン測定を行い、現状で可能な改良を行った。しかし、ラマン分光器に設置してある紫外検知器の感度が充分高くないため、細胞構造解析への応用には至っていない。今後、超高感度紫外検知器の採用をはじめ、更なる改良を行うことにより、細胞構造解析に充分応用可能な高性能紫外顕微ラマン分光システムを完成させることを計画している。

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  • 高性能マルチチャンネル紫外ラマン分光装置の試作

    研究課題/領域番号:02554018

    1990年 - 1991年

    制度名:科学研究費助成事業

    研究種目:試験研究(B)

    提供機関:日本学術振興会

    原田 一誠, 池田 壮, 外山 聡, 橋本 慎二, 小林 隆男

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    配分額:14900000円 ( 直接経費:14900000円 )

    迷光による妨害がなく低波数領域の測定が可能で、且つ明るい紫外ラマン分光器を設計製作した。主分光器はf=575mm(F6.3)のツェルニ-タ-ナ-型シングルポリクロメ-タ-であり、4320gr/mmのホログラフィック回折格子(効率:220nmで約30%)を装備した。また、レイリ-光カットのためツェルニ-タ-ナ-型前置プリズム分光器(f=200mm)を取り付けた。市販器では強いレイリ-散乱を取り除くためにゼロ分散のフィルタ-分光器を取り付けているが、我々の分光器では光学素子の数を少なくしてスル-プットを向上させるため、一度分散させたスペクトルを白色光に戻すことなく中間スリット上に結像させ、スリットを適当に閉じることによりレイリ-光をカットした。中間スリット上での分散は、240nm励起の場合約1000cm^<-1>/mmであった。分散素子には合成石英製のリトロ-プリズムを用いた。プリズムは紫外領域で分散が大きく、また透過率は広い波長範囲にわたって一定であるという特徴を有する。試料からのラマン光集光系には紫外用のアクロマティックレンズを用いた。検出器にはLN/CCD1152を用いた。主分光器のみの場合、レイリ-散乱の少ないサンプルであればある程度測定可能であったが、タンパク質などの分子量の大きいものや濁っている試料では迷光の影響が強く測定は困難であった。しかし、前置プリズム分光器を取り付けた結果、入射スリット200μm、中間スリット1.5mmで、300cm^<-1>からほとんど迷光の影響のないスペクトルを得ることができた。したがって、この方法はスル-プットを落とすことなくかなりの低波数領域まで測定できる有効な方法であることがわかった。

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  • 紫外共鳴ラマン及びNMR分光法による薬物で誘起される核酸構造変化の研究

    研究課題/領域番号:02771680

    1990年

    制度名:科学研究費助成事業

    研究種目:奨励研究(A)

    提供機関:日本学術振興会

    外山 聡

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    配分額:800000円 ( 直接経費:800000円 )

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  • 紫外共鳴ラマン分光による調節蛋白一遺伝子相互作用とその動的過程

    研究課題/領域番号:62430004

    1987年 - 1990年

    制度名:科学研究費助成事業

    研究種目:一般研究(A)

    提供機関:日本学術振興会

    原田 一誠, 外山 聡, 橋本 慎二, 内多 潔, 竹内 英夫, 廣谷 恵理, 古川 行夫

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    配分額:24700000円 ( 直接経費:24700000円 )

    本研究は3つの段階に分けられる。第1は紫外ラマン分光装置の製作,第2はタンパク質,核酸の高次構造を反映する紫外ラマンマ-カ-バンドの表の充実,第3は,第1と第2の成果を踏まえて、遺伝情報の転写を調節する調節タンパク質の紫外共鳴ラマンスペクトルを測定,解析して,その調節機構の一端を構造化学的に理解することである。
    1.紫外ラマン分光装置の製作:既存の可視ラマン分光装置を改良し,紫外光源としてNd:YAGレ-ザ-(第2,3,4,5高調波)とラマンシフタ-を併用し,マルチチャンネル紫外ラマン分光装置を作製した。
    2.タンバク質・核酸構造マ-カ-バンド表の充実と応用:タンパク質主鎖のアミド結合,イミド結合(Pro),芳香族側鎖(Trp,Tyr,Phe,His),核塩法であるプリン,ピリミジン環の紫外ラマンバンドに関する基礎的な研究を行い,「ラマンマ-カ-バンド表」の充実を行った。また,ス-パ-オキシドジスムタ-ゼやバクテリオロドプシンの紫外共鳴ラマンスペクトルを初めて観測し,表に基づいて解析して有用な構造知見を得た。
    3.調節タンバク質CRPとそのcAMP複合体の水溶液中の構造:調節タクパク質の1つであるcAMP受容タンパク質(CRP)は2量体として存在し,cAMP取り込みにより構造変化して特定の塩基配宣列に強く結合する。CRP同士が会合していない希薄溶液(〜50μM)について紫外鳴ラマンスペクトルを測定し解析したところ、一方のサブユニットの逆平行βバレルにcAMPが取り込まれると,そのサブユニットのみならず他方のβバレル構造も大きく変化することがわかった。また,取り込まれたcAMPはsyn型であり,アデニン環のN7位,C6NH_2位とタンパク質との水素結合により安定化されている。

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