2021/09/24 更新

写真a

オチアイ アキヒト
落合 秋人
OCHIAI Akihito
所属
教育研究院 自然科学系 生産デザイン工学系列 准教授
工学部 工学科 准教授
職名
准教授
外部リンク

学位

  • 博士(農学) ( 2008年3月   京都大学 )

研究分野

  • ライフサイエンス / 食品科学

  • ナノテク・材料 / 生物分子化学  / 生理活性物質

  • ものづくり技術(機械・電気電子・化学工学) / バイオ機能応用、バイオプロセス工学

経歴(researchmap)

  • 新潟大学   工学部工学科   准教授

    2020年1月 - 現在

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  • 新潟大学   自然科学系材料生産システム専攻   准教授

    2020年1月 - 現在

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  • 新潟大学   工学部 工学科   助教

    2017年4月 - 2019年12月

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  • 新潟大学   自然科学研究科 材料生産システム専攻   助教

    2010年4月 - 2019年12月

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  • 新潟大学   工学部 機能材料工学科 材料開発工学   助教

    2010年4月 - 2017年3月

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経歴

  • 新潟大学   工学部 工学科   准教授

    2020年1月 - 現在

  • 新潟大学   工学部 工学科   助教

    2017年4月 - 2019年12月

  • 新潟大学   自然科学研究科 材料生産システム専攻   助教

    2010年4月 - 2019年12月

  • 新潟大学   材料開発工学   助教

    2010年4月 - 2017年3月

所属学協会

 

論文

  • Crystal structure of rice defensin OsAFP1 and molecular insight into lipid-binding 査読

    Akihito Ochiai, Kodai Ogawa, Minami Fukuda, Masami Suzuki, Kosuke Ito, Takaaki Tanaka, Yoshiyuki Sagehashi, Masayuki Taniguchi

    Journal of Bioscience and Bioengineering(印刷中)   2020年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

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  • Identification of cationic peptides derived from low protein rice by-products and evaluation of their multifunctional activities. 査読

    Masayuki Taniguchi, Ryousuke Aida, Kazuki Saito, Riku Oya, Akihito Ochiai, Eiichi Saitoh, Takaaki Tanaka

    Journal of bioscience and bioengineering   129 ( 3 )   307 - 314   2020年3月

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    記述言語:英語  

    Low protein rice (LPR) by-products were used as a source of novel multifunctional cationic peptides. The LPR by-products were separated by ampholyte-free isoelectric focusing (autofocusing) into 20 fractions containing peptides with different isoelectric points (pIs). Subsequently, the antimicrobial activity of each fraction was evaluated against four pathogenic microorganisms. In addition, the cationic peptides from fractions exhibiting antimicrobial activity were purified using reversed-phase high-performance liquid chromatography and identified using matrix-assisted laser/desorption ionization-time-of-flight mass spectroscopy. Of the 11 cationic peptides identified, five peptides with pI values greater than 9.31 and net charges greater than +2 were chemically synthesized for multiple functionalities, including antimicrobial, lipopolysaccharide (LPS)-neutralizing, and angiogenic activities. Among these five cationic peptides, only LPR-KRK, which had a net charge of +9, exhibited antimicrobial activity against three of the four pathogenic microorganisms tested. Chromogenic LPS-neutralizing assays using Limulus amebocyte lysate showed that the 50% effective concentrations of these five peptides were between 0.11 and 3.09 μM. Tube-formation assays using human umbilical vein endothelial cells showed that all five peptides exhibited significant angiogenic activity at 1 μM and 10 μM, while none exhibited hemolytic activity toward mammalian red blood cells at concentrations up to 500 μM. Our results demonstrate that these five cationic peptides exhibit multiple biological functionalities with little or no hemolytic activity. Thus, fractions containing cationic peptides obtained from LPR by-products have the potential to be used as dietary supplements and functional ingredients in food products.

    DOI: 10.1016/j.jbiosc.2019.09.009

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  • Identification and characterization of multifunctional cationic peptides from enzymatic hydrolysates of soybean proteins. 査読

    Masayuki Taniguchi, Ryousuke Aida, Kazuki Saito, Toyotaka Kikura, Akihito Ochiai, Eiichi Saitoh, Takaaki Tanaka

    Journal of bioscience and bioengineering   129 ( 1 )   59 - 66   2020年1月

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    記述言語:英語  

    In this study, we used the commercial soybean protein hydrolysate Hinute-DC6 as a novel starting material from which to purify and identify multifunctional cationic peptides. After fractionation, Hinute-DC6 was separated into 20 fractions with varying isoelectric points (pI) by ampholyte-free isoelectric focusing (autofocusing). Subsequently, we purified and identified the cationic peptides from fractions 19 and 20, which had pI values greater than 12, using reversed-phase high-performance liquid chromatography and matrix-assisted laser/desorption ionization-time-of-flight mass spectrometry. Of the 83 cationic peptides identified, 14 had high pI values and net charges greater than +2, and were chemically synthesized and assayed for various bioactivities, including hemolytic, antimicrobial, lipopolysaccharide (LPS)-neutralizing, and angiogenic activities. None of the 14 cationic peptides tested exhibited hemolytic activity toward mammalian red blood cells at concentrations up to 1000 μM. Five of the cationic peptides exhibited antimicrobial activities against at least one of four human-pathogenic microorganisms tested. In addition, in chromogenic LPS-neutralizing assays using Limulus amebocyte lysates, the 50% effective concentrations of these 14 peptides were between 0.069 and 5.2 μM. Tube-formation assays in human umbilical vein endothelial cells showed that each of the 14 cationic peptides exhibited significant angiogenic activities at 10 μM, with values similar to those of the positive control LL-37. Our results demonstrate that the 14 identified cationic peptides have multiple functions with negligible hemolytic activity. These data indicate that the cationic peptides isolated from Hinute-DC6 and fractions containing these cationic peptides have the potential to be used as multifunctional ingredients for healthcare applications.

    DOI: 10.1016/j.jbiosc.2019.06.016

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  • Wound healing activity and mechanism of action of antimicrobial and lipopolysaccharide-neutralizing peptides from enzymatic hydrolysates of rice bran proteins. 査読

    Masayuki Taniguchi, Kazuki Saito, Ryousuke Aida, Akihito Ochiai, Eiichi Saitoh, Takaaki Tanaka

    Journal of bioscience and bioengineering   128 ( 2 )   142 - 148   2019年8月

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    記述言語:英語  

    In our previous study, we identified multifunctional cationic peptides from enzymatic hydrolysates of rice bran proteins (RBPs) that have antimicrobial and lipopolysaccharide-neutralizing activities. In this study, we investigated the potential of the peptides RBP-LRR, RBP-EKL, and RBP-SSF to promote proliferation, angiogenesis (tube formation), and migration in human umbilical vein endothelial cells (HUVECs). To determine mechanisms of wound healing actions, angiogenic and migration-promoting activities of these peptides were evaluated following pretreatments of HUVECs with specific inhibitors. In these experiments, the cationic peptides RBP-LRR, RBP-EKL, and RBP-SSF induced cell proliferation at low concentrations of 0.1 μM or 1 μM. Moreover, the three cationic peptides had angiogenic activities at concentrations more than 1 μM in tube formation assays, and their effects were similar to those of LL-37. Subsequent scratch migration assays exhibited that RBP-LRR, RBP-EKL, and RBP-SSF promote wound closure at optimum concentrations of 10, 10, and 0.1 μM, respectively. In further studies, we performed tube formation assays using HUVECs pretreated with SU5416, which inhibits vascular endothelial growth factor (VEGF) receptors, and suggested the possibility that the three cationic peptides induce angiogenesis by activating VEGF receptors. In corresponding scratch migration assays using HUVECs, pretreatment with the proliferation inhibitor mitomycin C did not alter the effects of RBP-LRR and RBP-EKL, and significant contribution to wound closure were mediated by cell migration regardless of proliferation rates. In contrast, RBP-SSF contributed to wound closure exclusively by promoting cell proliferation. The present data indicate that RBP-LRR, RBP-EKL, and RBP-SSF are candidates for use as wound healing agents.

    DOI: 10.1016/j.jbiosc.2019.02.002

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  • Protein adsorption characteristics of nanoparticle-assembled hollow microspheres of hydroxyapatite and their composites with PLLA microporous membranes. 査読

    Tanaka T, Takai Y, Nagase A, Teraguchi K, Minbu H, Ochiai A, Kimura I, Taniguchi M

    Heliyon   5 ( 4 )   e01490   2019年4月

  • Identification and characterization of multifunctional cationic peptides from traditional Japanese fermented soybean Natto extracts. 査読

    Masayuki Taniguchi, Ryousuke Aida, Kazuki Saito, Akihito Ochiai, Satoshi Takesono, Eiichi Saitoh, Takaaki Tanaka

    Journal of bioscience and bioengineering   127 ( 4 )   472 - 478   2019年4月

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    記述言語:英語  

    In this study, we investigated the lipopolysaccharide (LPS)-neutralizing and angiogenic activities of cationic peptides derived from the traditional Japanese fermented product Natto, which is made by fermenting cooked soybeans using Bacillus subtilis. Initially, we prepared 20 fractions of Natto extracts with various isoelectric points (pI's) using ampholyte-free isoelectric focusing (autofocusing). Cationic peptides were then purified from fractions 19 and 20, whose pH values were greater than 12, using reversed-phase high-performance liquid chromatography, and were identified using matrix-assisted laser/desorption ionization-time-of-flight mass spectroscopy. Among the 13 identified cationic peptides, seven (KFNKYGR, FPFPRPPHQK, GQSSRPQDRHQK, QRFDQRSPQ, ERQFPFPRPPHQK, GEIPRPRPRPQHPE, and EQPRPIPFPRPQPR) had pI's greater than 9.5, positive net charges, and differing molecular weights. These peptides were then chemically synthesized and applied to chromogenic LPS-neutralizing assays using Limulus amebocyte lysates, and 50% effective (neutralizing) concentrations of 2.6-5.5 μM were demonstrated. In addition, tube formation assays in human umbilical vein endothelial cells revealed angiogenic activities for all but one (GEIPRPRPRPQHPE) of these seven cationic peptides, with increases in relative tube lengths of 23-31% in the presence of peptides at 10 μM. Subsequent experiments showed negligible hemolytic activity of these peptides at concentrations of up to 500 μM in mammalian red blood cells. Collectively, these data demonstrate that six cationic peptides from Natto extracts, with the exception of GEIPRPRPRPQHPE, have LPS-neutralizing and angiogenic activities but do not induce hemolysis.

    DOI: 10.1016/j.jbiosc.2018.09.016

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  • Cationic peptides from enzymatic hydrolysates of soybean proteins exhibit LPS-neutralizing and angiogenic activities. 査読

    Masayuki Taniguchi, Yusuke Noda, Ryousuke Aida, Kazuki Saito, Akihito Ochiai, Eiichi Saitoh, Takaaki Tanaka

    Journal of bioscience and bioengineering   127 ( 2 )   176 - 182   2019年2月

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    記述言語:英語  

    In this study, we prepared fractions containing multifunctional cationic peptides by separating the commercial soybean protein hydrolysate Hinute-AM into 20 fractions. These fractions contained peptides with various isoelectric points (pI), as indicated by ampholyte-free isoelectric focusing (autofocusing). Thus, we purified and identified the cationic peptides from fractions 19 and 20, which had pH values greater than 10, using reversed-phase high-performance liquid chromatography and matrix-assisted laser/desorption ionization-time-of-flight mass spectroscopy. Among 19 identified cationic peptides, NKNAKPPSPR, PGKKNAIV, KSGPGMSPR, NVSKPPRVV, RKVGAGGRKPLG, and LPCVIGGVPKRV had high pI values and were included as chemically synthesized peptides in assays of various functions, including lipopolysaccharide (LPS)-neutralizing and angiogenic activities. Chromogenic LPS-neutralizing assays using Limulus amebocyte lysates showed that 50% effective concentrations of these six peptides were between 1.63 and 2.65 μM, and were higher than that (0.12 μM) of polymyxin B. Moreover, in tube-formation assays in human umbilical vein endothelial cells, all of the six cationic peptides except LPCVIGGVPKRV exhibited angiogenic activities similar to those of the positive control LL-37. In addition, the six identified cationic peptides had no hemolytic activity at concentrations up to 500 μM in mammalian red blood cells. Our results demonstrate that five of the identified cationic peptides, excluding LPCVIGGVPKRV, have multiple functions and little or no hemolytic activity. These data indicate that fractions containing cationic peptides from Hinute-AM have the potential to be used as dietary supplements and functional ingredients in food products.

    DOI: 10.1016/j.jbiosc.2018.07.013

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  • Peptides from rice endosperm protein restrain periodontal bone loss in mouse model of periodontitis. 査読 国際誌

    Hikaru Tamura, Tomoki Maekawa, Hisanori Domon, Takumi Hiyoshi, Daisuke Yonezawa, Kosuke Nagai, Akihito Ochiai, Masayuki Taniguchi, Koichi Tabeta, Takeyasu Maeda, Yutaka Terao

    Archives of oral biology   98   132 - 139   2019年2月

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    記述言語:英語  

    OBJECTIVE: Food-derived peptides have been reported to exhibit antibacterial activity against periodontal pathogenic bacteria. However, no effect has been shown on inflammation and bone resorption in periodontal pathology. The overall objective of the current study was to investigate how rice peptides influence biological defense mechanisms against periodontitis-induced inflammatory bone loss, and identify their novel functions as a potential anti-inflammatory drug. DESIGN: The expression of inflammatory and osteoclast-related molecules was examined in mouse macrophage-derived RAW 264.7 cell cultures using qPCR. Subsequently, the effect of these peptides on inflammatory bone loss in mouse periodontitis was examined using a mouse model of tooth ligation. Briefly, periodontal bone loss was induced for 7 days in mice by ligating the maxillary second molar and leaving the contralateral tooth un-ligated (baseline control). The mice were microinjected daily with the peptide in the gingiva until the day before euthanization. One week after the ligation, TRAP-positive multinucleated cells (MNCs) were enumerated from five random coronal sections of the ligated sites in each mouse. RESULTS: Rice peptides REP9 and REP11 significantly inhibited transcription activity of inflammatory and osteoclast-related molecules. Local treatment with the rice peptides, in mice subjected to ligature-induced periodontitis, inhibited inflammatory bone loss, explaining the decreased numbers of osteoclasts in bone tissue sections. CONCLUSION: Therefore, these data suggested that the rice peptides possess a protective effect against periodontitis.

    DOI: 10.1016/j.archoralbio.2018.11.021

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  • Poly(L-lactic acid) depth filter membrane prepared by nonsolvent-induced phase separation with the aid of a nonionic surfactant 査読

    H. Minbu, H. Mizuno, Y. Shibuya, A. Ochiai, M. Taniguchi, T. Tanaka

    Journal of Chemical Engineering of Japan   52 ( 1 )   75 - 82   2019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)  

    DOI: 10.1252/jcej.18we084

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  • Rice defensin OsAFP1 is a new drug candidate against human pathogenic fungi 査読

    A. Ochiai, K. Ogawa, M. Fukuda, M. Ohori, T. Kanaoka, T. Tanaka, M. Taniguchi, Y. Sagehashi

    Scientific Reports   8 ( 1 )   11434   2018年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1038/s41598-018-29715-w

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  • The antimicrobial and anti-endotoxic peptide AmyI-1-18 from rice α-amylase and its [N3L] analog promote angiogenesis and cell migration 査読 国際誌

    M. Taniguchi, A. Ochiai, T. Namae, K. Saito, T. Kato, E. Saitoh, T. Tanaka

    Peptides   104   78 - 84   2018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)  

    DOI: 10.1016/j.peptides.2018.04.017

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  • The PBII gene of the human salivary proline-rich protein P-B produces another protein, Q504X8, with an opiorphin homolog, QRGPR 査読

    Eiichi Saitoh, Takuya Sega, Akane Imai, Satoko Isemura, Tetsuo Kato, Akihito Ochiai, Masayuki Taniguchi

    Archives of Oral Biology   88   10 - 18   2018年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Elsevier Ltd  

    Objectives The NCBI gene database and human-transcriptome database for alternative splicing were used to determine the expression of mRNAs for P-B (SMR3B) and variant form of P-B. The translational product from the former mRNA was identified as the protein named P-B, whereas that from the latter has not yet been elucidated. In the present study, we investigated the expression of P-B and its variant form at the protein level. Design To identify the variant protein of P-B, (1) cationic proteins with a higher isoelectric point in human pooled whole saliva were purified by a two dimensional liquid chromatography
    (2) the peptide fragments generated from the in-solution of all proteins digested with trypsin separated and analyzed by MALDI-TOF-MS
    and (3) the presence or absence of P-B in individual saliva was examined by 15% SDS-PAGE. Results The peptide sequences (I37PPPYSCTPNMNNCSR52, C53HHHHKRHHYPCNYCFCYPK72, R59HHYPCNYCFCYPK72 and H60HYPCNYCFCYPK72) present in the variant protein of P-B were identified. The peptide sequence (G6PYPPGPLAPPQPFGPGFVPPPPPPPYGPGR36) in P-B (or the variant) and sequence (I37PPPPPAPYGPGIFPPPPPQP57) in P-B were identified. The sum of the sequences identified indicated a 91.23% sequence identity for P-B and 79.76% for the variant. There were cases in which P-B existed in individual saliva, but there were cases in which it did not exist in individual saliva. Conclusions The variant protein is produced by excising a non-canonical intron (CC-AC pair) from the 3′-noncoding sequence of the PBII gene. Both P-B and the variant are subject to proteolysis in the oral cavity.

    DOI: 10.1016/j.archoralbio.2018.01.006

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  • Cationic peptides from peptic hydrolysates of rice endosperm protein exhibit antimicrobial, LPS-neutralizing, and angiogenic activities 査読

    Masayuki Taniguchi, Junya Kawabe, Ryu Toyoda, Toshiki Namae, Akihito Ochiai, Eiichi Saitoh, Takaaki Tanaka

    PEPTIDES   97   70 - 78   2017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)   出版者・発行元:ELSEVIER SCIENCE INC  

    In this study, we hydrolyzed rice endosperm protein (REP) with pepsin and generated 20 fractions containing multifunctional cationic peptides with varying isoelectric point (pI) values using ampholyte-free isoelectric focusing (autofocusing). Subsequently, we determined antimicrobial activities of each fraction against the pathogens Prophyromonas gingivalis, Propionibacterium acnes, Streptocossus mutans, and Candida albicans. Fractions 18, 19, and 20 had pI values greater than 12 and exhibited antimicrobial activity against P. gingivalis, P. acnes, and C. albicans, but not against S. mutans. In further experiments, we purified and identified cationic peptides from fractions 18, 19, and 20 using reversed-phase high-performance liquid chromatography and matrix-assisted laser/desorption ionization-time-of-flight mass spectroscopy. We also chemically synthesized five identified peptides (RSVSKSR, RRVIEPR, ERFQPMFRRPG, RVRQNIDNPNRADTYNPRAG, and VVRRVIEPRGLL) with pI values greater than 10.5 and evaluated antimicrobial, lipopolysaccharide (LPS)-neutralizing, and angiogenic activities. Among these synthetic peptides, only VVRRVIEPRGLL exhibited antimicrobial activity against P. gingivalis, with an IC50 value of 87 mu M. However, all five cationic peptides exhibited LPS-neutralizing and angiogenic activities with little or no hemolytic activity against mammalian red blood cells at functional concentrations. These present data show dual or multiple functions of the five identified cationic peptides with little or no hemolytic activity. Therefore, fractions containing cationic peptides from REP hydrolysates have the potential to be used as dietary supplements and functional ingredients in food products.

    DOI: 10.1016/j.peptides.2017.09.019

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  • Identification and characterization of multifunctional cationic peptides derived from peptic hydrolysates of rice bran protein 査読

    Masayuki Taniguchi, Mitsuhiro Kameda, Toshiki Namae, Akihito Ochiai, Eiichi Saitoh, Takaaki Tanaka

    JOURNAL OF FUNCTIONAL FOODS   34   287 - 296   2017年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ELSEVIER SCIENCE BV  

    In this study, to prepare the fraction containing multifunctional cationic peptides, we first hydrolyzed rice bran protein (RBP) with pepsin. We separated the enzymatic hydrolysate of RBP into 20 fractions containing peptides with different isoelectric point (pI) values by ampholyte-free isoelectric focusing (autofocusing). Subsequently, we examined the antimicrobial activity of each fraction against four pathogens. In addition, we purified the cationic peptides from fractions exhibiting antimicrobial activity by reversed phase high-performance liquid chromatography and identified them by matrix-assisted laser/desorption ionization-time-of-flight mass spectroscopy. Of five cationic peptides identified, we chemically synthesized three peptides with high pI values and evaluated their multiple functions, including antimicrobial, lipopolysaccharide-neutralizing and angiogenic activities. Our results demonstrated that the three identified cationic peptides exhibited multiple functions with little or no haemolytic activity. Fractions containing cationic peptides obtained from RBP hydrolysate have the potential to be used as dietary supplements and functional ingredients in food products. (C) 2017 Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.jff.2017.04.046

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  • Identification and characterization of multifunctional cationic and amphipathic peptides from soybean proteins 査読

    Masayuki Taniguchi, Kengo Saito, Takafumi Nomoto, Toshiki Namae, Akihito Ochiai, Eiichi Saitoh, Takaaki Tanaka

    BIOPOLYMERS   108 ( 4 )   e23023   2017年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:WILEY  

    In this study, we identified and chemically synthesized three cationic and amphipathic peptides (Glycinin-17, BCAS-16, and BCBS-11) from soybean proteins. These peptides had high isoelectric points, high positive net charges, and included multiple hydrophobic amino acids. Subsequently, we identified multiple functions of these peptides, including antimicrobial, lipopolysaccharide-neutralizing, and angiogenic activities, and examined their cytotoxic activities against mammalian red blood cells. Glycinin-17, BCAS-16, and BCBS-11 exhibited antimicrobial activity against Porphyromonas gingivalis and Candida albicans whereas Glycinin-17 did not possess antimicrobial effects on Propionibacterium acnes and Streptococcus mutans. Membrane-depolarization assays and flow cytometric analyses showed that the antimicrobial properties of Glycinin-17, BCAS-16, and BCBS-11 against P. gingivalis, P. acnes, and S. mutans were dependent on membrane-disrupting potential. In contrast, major antimicrobial activities of these peptides against C. albicans were dependent on interactions with targets other than cell membranes. Furthermore, chromogenic Limulus amebocyte lysate assays showed that 50% effective concentrations (EC50, 0.12-0.31 mu M) of these three peptides neutralize LPS with similar potency (EC50: 0.11 mu M) to that of polymyxin B. Moreover, tube-formation assays in human umbilical vein endothelial cells showed similar angiogenic activities of the three peptides as that following treatment with LL-37. Although BCAS-16 exhibited hemolytic activity, the rate of hemolysis for Glycinin-17 and BCBS-11 in the presence of 500-mu M Glycinin-17 and BCBS-11 was less than 2%. These results demonstrate that cationic and amphipathic peptides from soybean proteins, particularly Glycinin-17 and BCBS-11, have potential as multifunctional ingredients for healthcare applications.

    DOI: 10.1002/bip.23023

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  • Bioactive peptides hidden in human salivary proteins 査読

    Eiichi Saitoh, Masayuki Taniguchi, Akihito Ochiai, Tetsuo Kato, Akane Imai, Satoko Isemura

    Journal of Oral Biosciences   59 ( 2 )   71 - 79   2017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)   出版者・発行元:Japanese Association for Oral Biology  

    Background Extensive peptidomic studies of human saliva have resulted in considerable advances in the field of proteomics. As the next generation in salivary research, a comprehensive understanding of the biological functions of in vivo peptides generated by proteolysis in the oral cavity has been long awaited. A cyclopedic functional analysis of salivary peptides may bring promising therapeutic agents and novel clinical applications.Highlight: (1) This review article refers to bioactive peptides hidden in salivary parent proteins. (2) Functions of the peptides as anti-microbial, anti-viral, wound-closing, and anti-pain are described. (3) Biological significances of the repeated structures in salivary proline-rich proteins are emphasized. Conclusion Human salivary proteins have the ability to generate bioactive peptides upon proteolytic cleavage.

    DOI: 10.1016/j.job.2016.11.005

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  • Effects of arginine and leucine substitutions on anti-endotoxic activities andmechanisms of action of cationic and amphipathic antimicrobial octadecapeptide from rice α-amylase 査読

    M. Taniguchi, A. Ochiai, R. Toyoda, T. Sato, E. Saitoh, T. Kato, T. Tanaka

    Journal of peptide science   23 ( 3 )   252 - 260   2017年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1002/psc.2983

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  • Antimicrobial activity against Porphyromonas gingivalis and mechanism of action of the cationic octadecapeptide Amyl-1-18 and its amino acid-substituted analogs 査読

    Masayuki Taniguchi, Akihito Ochiai, Kiyoshi Takahashi, Shun-ichi Nakamichi, Takafumi Nomoto, Eiichi Saitoh, Tetsuo Kato, Takaaki Tanakal

    JOURNAL OF BIOSCIENCE AND BIOENGINEERING   122 ( 6 )   652 - 659   2016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)   出版者・発行元:SOC BIOSCIENCE BIOENGINEERING JAPAN  

    The antimicrobial peptide Amyl-1-18 is a cationic alpha-helical octadecapeptide derived from alpha-amylase in rice (Oryza sativa L. japonica) that contains four cationic amino acid residues (two arginines and two lysines). To enhance the antibacterial activity of Amyl-1-18 against Porphyromonas gingivalis (a bacterium associated with periodontal disease), we synthesized 12 analogs bearing substitutions with alanine, leucine, and/or arginine that were designed based on helical wheel projections and investigated their antibacterial properties. The antibacterial properties of four analogs bearing substitution of a single arginine or lysine with alanine were almost similar to those of Amyl-1-18, suggesting that the antibacterial properties depend on the presence of three cationic amino acid residues. Of three single arginine-substituted analogs, Amyl-1-18(G12R) exhibited an antibacterial activity 2.8-fold higher [50% growth-inhibitory concentration (IC50): 4.6 mu M] than that of Amyl-1-18 (IC50: 13 mu M). Likewise, the antibacterial properties of two single leucine-substituted analogs were significantly enhanced; in particular, Amyl-1-18(N3L) exhibited an antibacterial activity (IC50: 2.5 mu M) 5.2-fold higher than that of Amyl-1-18. The hemolytic activity of Amyl-1-18(N3L) against mammalian red blood cells was low (2% at 50 mu M). A membrane-depolarization assay using a membrane potential-sensitive fluorescent dye revealed that, similar to Amyl-1-18, the antibacterial activity of Amyl-1-18(N3L) was not dependent on its membrane-disrupting activity. Our results demonstrate that the antibacterial properties of Amyl-1-18 against P. gingivalis are significantly improved, without a significant increase in hemolytic activity, by replacing asparagine with leucine at position 3. (C) 2016, The Society for Biotechnology, Japan. All rights reserved.

    DOI: 10.1016/j.jbiosc.2016.05.008

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  • Preparation of a poly(L-lactic acid) membrane scaffold with open finger-like pores prepared by a nonsolvent-induced phase separation method with the aid of a surfactant 査読

    H. Minbu, T. Kawase, A. Ochiai, M. Taniguchi, T. Tanaka

    MEMBRANE   41 ( 6 )   304 - 310   2016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)  

    DOI: 10.5360/membrane.41.304

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  • AmyI-1–18, a cationic α-helical antimicrobial octadecapeptide derived from α-amylase in rice, inhibits the translation and folding processes in a protein synthesis system 査読

    M. Taniguchi, A. Ochiai, S. Fukuda, T. Sato, E. Saitoh, T. Kato, T. Tanaka

    Journal of Bioscience and Bioengineering   122 ( 4 )   385 - 392   2016年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1016/j.jbiosc.2016.03.004

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  • Rice Bran Protein as a Potent Source of Antimelanogenic Peptides with Tyrosinase Inhibitory Activity 査読

    Akihito Ochiai, Seiya Tanaka, Takaaki Tanaka, Masayuki Taniguchi

    JOURNAL OF NATURAL PRODUCTS   79 ( 10 )   2545 - 2551   2016年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:AMER CHEMICAL SOC  

    Rice (Oryza sativa) is consumed as a staple food globally, and rice bran, the byproduct, is an unused biomass that is ultimately discarded as waste. Thus, in the present study, a technique for producing tyrosinase inhibitory peptides from rice bran protein (RBP) was developed. Simultaneous treatment of RBP with chymotrypsin and trypsin produced numerous peptides. Subsequently, six tyrosinase inhibitory peptides were isolated from the hydrolysate fractions in a multistep purification protocol, and their amino acid sequences were determined. Three of these peptides had a C-terminal tyrosine residue and exhibited significant inhibitory effects against tyrosinase-mediated monophenolase reactions. Furthermore, peptide CT-2 (Leu-Gln-Pro-Ser-His-Tyr) potently inhibited melanogenesis in mouse B16 melanoma cells without causing cytotoxicity, suggesting the potential of CT-2 as an agent for melanin-related skin disorder treatment. The present data indicate that RBP is a potent source of tyrosinase inhibitory peptides and that simultaneous treatment of RBP with chymotrypsin and trypsin efficiently produces these peptides.

    DOI: 10.1021/acs.jnatprod.6b00449

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  • New tyrosinase inhibitory decapeptide: Molecular insights into the role of tyrosine residues 査読

    Akihito Ochiai, Seiya Tanaka, Yuta Imai, Hisashi Yoshida, Takumi Kanaoka, Takaaki Tanaka, Masayuki Taniguchi

    JOURNAL OF BIOSCIENCE AND BIOENGINEERING   121 ( 6 )   607 - 613   2016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)   出版者・発行元:SOC BIOSCIENCE BIOENGINEERING JAPAN  

    Tyrosinase, a rate-limiting enzyme in melanin biosynthesis, catalyzes the hydroxylation of L-tyrosine to 3,4-dihydroxy-L-phenylalanine (L-dopa) (monophenolase reaction) and the subsequent oxidation of L-dopa to L-dopaquinone (diphenolase reaction). Thus, tyrosinase inhibitors have been proposed as skin-lightening agents; however, many of the existing inhibitors cannot be widely used in the cosmetic industry due to their high cytotoxicity and instability. On the other hand, some tyrosinase inhibitory peptides have been reported as safe. In this study, we found that the peptide TH10, which has a similar sequence to the characterized inhibitory peptide P4, strongly inhibits the monophenolase reaction with a half-maximal inhibitory concentration of 102 mu M. Seven of the ten amino acid residues in TH10 were identical to P4; however, TH10 possesses one N-terminal tyrosine, whereas P4 contains three tyrosine residues located at its N-terminus, center, and C-terminus. Subsequent analysis using sequence-shuffled variants indicated that the tyrosine residues located at the N-terminus and center of P4 have little to no contribution to its inhibitory activity. Furthermore, docking simulation analysis of these peptides with mushroom tyrosinase demonstrated that the active tyrosine residue was positioned close to copper ions, suggesting that TH10 and P4 bind to tyrosinase as a substrate analogue. (C) 2015 The Society for Biotechnology, Japan. All rights reserved.

    DOI: 10.1016/j.jbiosc.2015.10.010

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  • Inhibitory effects of a novel cationic dodecapeptide [CL(14–25)] derived from cyanate lyase of rice on endotoxic activities of LPSs from <i>Escherichia coli</i> and periodontopathic <i>Aggregatibacter actinomycetemcomitans</i> 査読

    S. Takayama, K. Hashimoto, E. Kokubu, M. Taniguchi, K. Tajima, A. Ochiai, E. Saitoh, A. Saito, K. Ishihara, T. Kato

    Microbial Pathogenesis   94   2 - 11   2016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)  

    DOI: 10.1016/j.micpath.2015.08.011

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  • Pyrrhocoricin, a proline-rich antimicrobial peptide derived from insect, inhibits the translation process in the cell-free Escherichia coli protein synthesis system 査読

    Masayuki Taniguchi, Akihito Ochiai, Hiroshi Kondo, Shun Fukuda, Yohei Ishiyama, Eiichi Saitoh, Tetsuo Kato, Takaaki Tanaka

    JOURNAL OF BIOSCIENCE AND BIOENGINEERING   121 ( 5 )   591 - 598   2016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)   出版者・発行元:SOC BIOSCIENCE BIOENGINEERING JAPAN  

    Previous studies have shown that pyrrhocoricin, a proline-rich antimicrobial peptide (PrAMP), killed sensitive species in a dose-dependent manner by specifically binding to DnaK. Here, on the basis of the finding that DnaK-deficient Escherichia coli strains are susceptible to PrAMPs, we used pyrrhocoricin to investigate internal targets other than DnaK. Using conventional antibiotics (bleomycin, streptomycin, and fosfomycin) that have known modes of action, first, we validated the availability of an assay using a cell-free rapid translation system (RTS), which is an in vitro protein synthesis system based on E. coli lysate, for evaluating inhibition of protein synthesis. We found that, similarly to bleomycin and streptomycin, pyrrhocoricin inhibited GFP synthesis in RTS in a concentration-dependent manner. In addition, blockage of transcription and translation steps in RTS was individually estimated using RT-PCR after gene expression to determine mRNA products and using sodium dodecyl sulfate-polyacrylamide gel electrophoresis to determine the amounts of GFP expressed from purified mRNA, respectively. The results demonstrated that this inhibition of GFP synthesis by pyrrhocoricin did not occur at the transcription step but rather at the translation step, in a manner similar to that of GFP synthesis by streptomycin, an inhibitor of the translation step by causing misreading of tRNA. These results suggest that RTS is a powerful assay system for determining if antimicrobial peptides inhibit protein synthesis and its transcription and/or translation steps. This is the first study to have shown that pyrrhocoricin inhibited protein synthesis by specifically repressing the translation step. (C) 2015, The Society for Biotechnology, Japan. All rights reserved.

    DOI: 10.1016/j.jbiosc.2015.09.002

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  • Effect of alanine, leucine, and arginine substitution on antimicrobial activity against <i>Candida albicans</i> and action mechanism of a cationic octadecapeptide derived from α-amylase of rice 査読

    M. Taniguchi, A. Ochiai, K. Takahashi, S. Nakamichi, T. Nomoto, E. Saitoh, T. Kato, T. Tanaka

    Biopolymer (Peptide Science)   106 ( 2 )   219 - 229   2016年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1002/bip.22817

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  • Endotoxin- neutralizing activity and mechanism of action of a cationic α-helical antimicrobial octadecapeptide derived from α-amylase of rice 査読

    M. Taniguchi, A. Ochiai, K. Matsushima, K. Tajima, T. Kato, E. Saitoh, T. Tanaka

    Peptides   75   101 - 108   2016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)  

    DOI: 10.1016/j.peptides.2015.11.006

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  • Structural studies on Laz, a promiscuous anticancer Neisserial protein 査読

    Wataru Hashimoto, Akihito Ochiai, Chang Soo Hong, Kousaku Murata, Ananda M. Chakrabarty

    BIOENGINEERED   6 ( 3 )   141 - 148   2015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)   出版者・発行元:TAYLOR & FRANCIS INC  

    Azurin and Laz (lipidated azurin) are 2 bacterial proteins with anticancer, anti-viral and anti-parasitic activities. Azurin, isolated from the bacterium Pseudomonas aeruginosa, termed Paz, demonstrates anticancer activity against a range of cancers but not against brain tumors. In contrast, Laz is produced by members of Gonococci/Meningococci, including Neisseria meningitides which can cross the blood-brain barrier to infect brain meninges. It has been previously reported that Laz has an additional 39 amino acid moiety, called an H.8 epitope, in the N-terminal part of the azurin moiety that allows Laz to cross the entry barrier to brain tumors such as glioblastomas. Exactly, how the H.8 epitope helps the azurin moiety of Laz to cross the entry barriers to attack glioblastoma cells is unknown. In this paper, we describe the structural features of the H.8 moiety in Laz using X-ray crystallography and demonstrate that while the azurin moiety of Laz adopts a beta-sandwich fold with 2 beta-sheets arranged in the Greek key motif, the H.8 epitope was present as a disordered structure outside the Greek key motif. Structures of Paz and H.8 epitope-deficient Laz are well superimposed. The structural flexibility of the H.8 motif in Laz explains the extracellular location of Laz in Neisseria where it can bind the key components of brain tumor cells to disrupt their tight junctions and allow entry of Laz inside the tumors to exert cytotoxicity.

    DOI: 10.1080/21655979.2015.1022303

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  • Preparation of poly(L-lactic acid) microfiltration membranes by a nonsolvent-induced phase separation method with the aid of surfactants 査読

    Hiromi Minbu, Akihito Ochiai, Tomoyuki Kawase, Masayuki Taniguchi, Douglas R. Lloyd, Takaaki Tanaka

    JOURNAL OF MEMBRANE SCIENCE   479   85 - 94   2015年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ELSEVIER SCIENCE BV  

    Microfiltration membranes of poly(L-lactic acid) (PLEA) have been prepared by a nonsolvent-induced phase separation method with the aid of surfactants. Surfactants with hydrophilic-lipophilic balance (HLB) values of 14.9-15.6 were found to be useful in reducing the shrinkage in thickness of the PLEA membrane. Among the surfactants examined, Tween 80 was the best for preparing microfiltration membranes. The surfactant allowed instantaneous phase separation and seemed to enhance the diffusion of water in the PLEA solution during structure formation. The membrane had asymmetric finger-like structures and showed low membrane resistance and high bacterial cell retention when the membrane was prepared from a 10 wt% PLEA solution in 1,4-dioxane containing 10 wt.% Tween 80. Bovine serum albumin molecules passed through the membrane suggesting that the membrane functions as a microfiltration membrane. The membrane was stable at 25 degrees C but degradable at 60 degrees C in wet conditions. The membrane can be applied as a compostable microfiltration membrane in food and biochemical industries. (C) 2015 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.memsci.2015.01.021

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  • Antimicrobial activity and mechanism of action of a novel cationic α-helical octadecapeptide derived from α-amylase of rice 査読

    M. Taniguchi, A. Ochiai, K. Takahashi, S. Nakamichi, T. Nomoto, E. Saitoh, T. Kato, T. Tanaka

    Peptide Science   104 ( 2 )   73 - 83   2015年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1002/bip.22605

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  • Contribution of cationic amino acids toward the inhibition of Arg-specific cysteine proteinase (Arg-gingipain) by the antimicrobial dodecapeptide, CL(14–25), from rice protein 査読

    M. Taniguchi, Y. Matsuhashi, T. K. Abe, Y. Ishiyama, E. Saitoh, T. Kato, A. Ochiai, T. Tanaka

    Peptide Science   102 ( 5 )   379 - 389   2014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)  

    DOI: 10.1002/bip.22525

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  • Crystal structure of α-amylase from <i>Oryza sativa</i>: molecular insights into enzyme activity and thermostability 査読

    A. Ochiai, H. Sugai, K. Harada, S. Tanaka, Y. Ishiyamaa, K. Ito, T. Tanaka, T. Uchiumi, M. Taniguchi, T. Mitsui

    Bioscience, Biotechnology, and Biochemistry   78 ( 6 )   989 - 997   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)  

    DOI: 10.1080/09168451.2014.917261

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  • α-Amylase is a potential growth inhibitor of <i>Porphyromonas gingivalis</i>, a periodontal pathogenic bacterium 査読

    A. Ochiai, K. Harada, K. Shibata, K. Hashimoto, Y. Ishiyama, T. Mitsui, T. Tanaka, M. Taniguchi

    Journal of Periodontal Research   49 ( 1 )   62 - 68   2014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)  

    DOI: 10.1111/jre.12079

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  • Effect of Substituting Arginine and Lysine with Alanine on Antimicrobial Activity and the Mechanism of Action of a Cationic Dodecapeptide (CL(14-25)), a Partial Sequence of Cyanate Lyase from Rice 査読

    Masayuki Taniguchi, Nobuteru Takahashi, Tomohiro Takayanagi, Atsuo Ikeda, Yohei Ishiyama, Eiichi Saitoh, Tetsuo Kato, Akihito Ochiai, Takaaki Tanaka

    BIOPOLYMERS   102 ( 1 )   58 - 68   2014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)   出版者・発行元:WILEY-BLACKWELL  

    The antimicrobial activity of analogs obtained by substituting arginine and lysine in CL(14-25), a cationic alpha-helical dodecapeptide, with alanine against Porphyromonas gingivalis, a periodontal pathogen, varied significantly depending on the number and position of cationic amino acids. The alanine-substituted analogs had no hemolytic activity, even at a concentration of 1 mM. The antimicrobial activities of CL(K20A) and CL(K20A, K25A) were 3.8-fold and 9.1-fold higher, respectively, than that of CL(14-25). The antimicrobial activity of CL(R15A) was slightly lower than that of CL(14-25), suggesting that arginine at position 15 is not essential but is important for the antimicrobial activity. The experiments in which the alanine-substituted analogs bearing the replacement of arginine at position 24 and/or lysine at position 25 were used showed that arginine at position 24 was crucial for the antimicrobial activity whenever lysine at position 25 was substituted with alanine. Helical wheel projections of the alanine-substituted analogs indicate that the hydrophobicity in the vicinity of leucine at position 16 and alanines at positions 18 and/or 21 increased by substituting lysine at positions 20 and 25 with alanine, respectively. The degrees of diSC(3)-5 release from P. gingivalis cells and disruption of GUVs induced by the alanine-substituted analogs with different positive charges were not closely related to their antimicrobial activities. The enhanced antimicrobial activities of the alanine-substituted analogs appear to be mainly attributable to the changes in properties such as hydrophobicity and amphipathic propensity due to alanine substitution and not to their extents of positive charge (cationicity). (C) 2013 Wiley Periodicals, Inc.

    DOI: 10.1002/bip.22399

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  • Antimicrobial activity and mechanism of action of a novel cationic α-helical dodecapeptide, a partial sequence of cyanate lyase from rice 査読

    N. Takei, N. Takahashi, T. Takayanagi, A. Ikeda, K. Hashimoto, M. Takagi, T. Hamada, E. Saitoh, A. Ochiai, T. Tanaka, M. Taniguchi

    Peptides   42   55 - 62   2013年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1016/j.peptides.2012.12.015

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  • Antimicrobial activity and mechanism of action of a novel cationic α-helical octadecapeptide derived from heat shock protein 70 of rice 査読

    M. Taniguchi, A. Ikeda, S. Nakamichi, Y. Ishiyama, E. Saitoh, T. Kato, A. Ochiai, T. Tanaka

    Peptides   48   147 - 155   2013年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1016/j.peptides.2013.08.011

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  • Structural Determinants of Discrimination of NAD(+) from NADH in Yeast Mitochondrial NADH Kinase Pos5 査読

    Takuya Ando, Kazuto Ohashi, Akihito Ochiai, Bunzo Mikami, Shigeyuki Kawai, Kousaku Murata

    JOURNAL OF BIOLOGICAL CHEMISTRY   286 ( 34 )   29984 - 29992   2011年8月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC  

    NAD kinase catalyzes the phosphorylation of NAD(+) to synthesize NADP(+), whereas NADH kinase catalyzes conversion of NADH to NADPH. The mitochondrial protein Pos5 of Saccharomyces cerevisiae shows much higher NADH kinase than NAD kinase activity and is therefore referred to as NADH kinase. To clarify the structural determinant underlying the high NADH kinase activity of Pos5 and its selectivity for NADH over NAD(+), we determined the tertiary structure of Pos5 complexed with NADH at a resolution of 2.0 angstrom. Detailed analysis, including a comparison of the tertiary structure of Pos5 with the structures of human and bacterial NAD kinases, revealed that Arg-293 of Pos5, corresponding to His-351 of human NAD kinase, confers a positive charge on the surface of NADH-binding site, whereas the corresponding His residue does not. Accordingly, conversion of the Arg-293 into a His residue reduced the ratio of NADH kinase activity to NAD kinase activity from 8.6 to 2.1. Conversely, simultaneous changes of Ala-330 and His-351 of human NAD kinase into Ser and Arg residues significantly increased the ratio of NADH kinase activity to NAD kinase activity from 0.043 to 1.39; human Ala-330 corresponds to Pos5 Ser-272, which interacts with the side chain of Arg-293. Arg-293 and Ser-272 were highly conserved in Pos5 homologs (putative NADH kinases), but not in putative NAD kinases. Thus, Arg-293 of Pos5 is a major determinant of NADH selectivity. Moreover, Ser-272 appears to assist Arg-293 in achieving the appropriate conformation.

    DOI: 10.1074/jbc.M111.249011

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  • Crystal structure of bacterial cell-surface alginate-binding protein with an M75 peptidase motif 査読

    Yukie Maruyama, Akihito Ochiai, Bunzo Mikami, Wataru Hashimoto, Kousaku Murata

    BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS   405 ( 3 )   411 - 416   2011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)   出版者・発行元:ACADEMIC PRESS INC ELSEVIER SCIENCE  

    A gram-negative Sphingomonas sp. A1 directly incorporates alginate polysaccharide into the cytoplasm via the cell-surface pit and ABC transporter. A cell-surface alginate-binding protein, Algp7, functions as a concentrator of the polysaccharide in the pit. Based on the primary structure and genetic organization in the bacterial genome, Algp7 was found to be homologous to an M75 peptidase motif-containing EfeO, a component of a ferrous ion transporter. Despite the presence of an M75 peptidase motif with high similarity, the Algp7 protein purified from recombinant Escherichia coli cells was inert on insulin B chain and N-benzoyl-Phe-Val-Arg-p-nitroanilide, both of which are substrates for a typical M75 peptidase. imelysin, from Pseudomonas aeruginosa. The X-ray crystallographic structure of Algp7 was determined at 2.10 angstrom resolution by single-wavelength anomalous diffraction. Although a metal-binding motif, HxxE, conserved in zinc ion-dependent M75 peptidases is also found in Algp7, the crystal structure of Algp7 contains no metal even at the motif. The protein consists of two structurally similar up-and-down helical bundles as the basic scaffold. A deep cleft between the bundles is sufficiently large to accommodate macromolecules such as alginate polysaccharide. This is the first structural report on a bacterial cell-surface alginate-binding protein with an M75 peptidase motif. (C) 2011 Elsevier Inc. All rights reserved.

    DOI: 10.1016/j.bbrc.2011.01.043

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  • Molecular identification of unsaturated uronate reductase prerequisite for alginate metabolism in Sphingomonas sp A1 査読

    Ryuichi Takase, Akihito Ochiai, Bunzo Mikami, Wataru Hashimoto, Kousaku Murata

    BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS   1804 ( 9 )   1925 - 1936   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)   出版者・発行元:ELSEVIER SCIENCE BV  

    In Sphingomonas sp. A1, alginate is degraded by alginate lyases to its constituent monosaccharides, which are nonenzymatically converted to an alpha-keto acid, namely, 4-deoxy-L-erythro-5-hexoseulose uronic acid (DEH). The properties of the DEH-metabolizing enzyme and its gene in strain A1 were characterized. In the presence of alginate, strain A1 cells inducibly produced an NADPH-dependent DEH reductase (A1-R) in their cytoplasm. Molecular cloning of the enzyme gene indicated that A1-R belonged to the short-chain dehydrogenase/reductase superfamily and catalyzed the conversion of DEH to 2-keto-3-deoxy-D-gluconic acid most efficiently at around pH 7.0 and 50 degrees C. Crystal structures of A1-R and its complex with NADP were determined at around 1.6 angstrom resolution by X-ray crystallography. The enzyme consists of three layers (alpha/beta/alpha) , with a coenzyme-binding Rossmann fold. NADP is surrounded by positively charged residues, and Gly-38 and Arg-39 are crucial for NADP binding. Site-directed mutagenesis studies suggest that Ser-150, Tyr-164, and Lys-168 located around the Rossmann fold constitute the catalytic triad. To our knowledge, this is the first report on molecular cloning and structure determination of a bacterial DEH reductase responsible for alginate metabolism. (C) 2010 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.bbapap.2010.05.010

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  • Crystal Structure of Exotype Alginate Lyase Atu3025 from Agrobacterium tumefaciens 査読

    Akihito Ochiai, Masayuki Yamasaki, Bunzo Mikami, Wataru Hashimoto, Kousaku Murata

    JOURNAL OF BIOLOGICAL CHEMISTRY   285 ( 32 )   24519 - 24528   2010年8月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC  

    Alginate, a major component of the cell wall matrix in brown seaweeds, is degraded by alginate lyases through a beta-elimination reaction. Almost all alginate lyases act endolytically on substrate, thereby yielding unsaturated oligouronic acids having 4-deoxy-L-erythro-hex-4-enepyranosyluronic acid at the nonreducing end. In contrast, Agrobacterium tumefaciens alginate lyase Atu3025, a member of polysaccharide lyase family 15, acts on alginate polysaccharides and oligosaccharides exolytically and releases unsaturated monosaccharides from the substrate terminal. The crystal structures of Atu3025 and its inactive mutant in complex with alginate trisaccharide (H531A/Delta GGG) were determined at 2.10- and 2.99-angstrom resolutions with final R-factors of 18.3 and 19.9%, respectively, by x-ray crystallography. The enzyme is comprised of an alpha/alpha-barrel + anti-parallel beta-sheet as a basic scaffold, and its structural fold has not been seen in alginate lyases analyzed thus far. The structural analysis of H531A/Delta GGG and subsequent site-directed mutagenesis studies proposed the enzyme reaction mechanism, with His(311) and Tyr(365) as the catalytic base and acid, respectively. Two structural determinants, i.e. a short alpha-helix in the central alpha/alpha-barrel domain and a conformational change at the interface between the central and C-terminal domains, are essential for the exolytic mode of action. This is, to our knowledge, the first report on the structure of the family 15 enzyme.

    DOI: 10.1074/jbc.M110.125450

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  • Mutational studies of the peptidoglycan hydrolase FlgJ of Sphingomonas sp strain A1 査読

    Yukie Maruyama, Akihito Ochiai, Takafumi Itoh, Bunzo Mikami, Wataru Hashimoto, Kousaku Murata

    JOURNAL OF BASIC MICROBIOLOGY   50 ( 4 )   311 - 317   2010年8月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:WILEY-V C H VERLAG GMBH  

    The flagellar protein FlgJ, a member of glycoside hydrolase family 73, has N- and C-terminal domains that are responsible for flagellar rod assembly and peptidoglycan hydrolysis, respectively. The crystal structure of the C-terminal domain of SPH1045 (SPH1045-C), the FlgJ from Sphingomonas sp. strain A1, showed a long cleft formed by two lobes, alpha and beta. In this study, seven site-specific mutants of residues in the cleft were prepared and analyzed. Enzyme activity was reduced most significantly in mutants E185A and Y281A, followed by E224A. A comparison of the crystal structure of the inactive mutant E185A with that of other related enzymes revealed that Glu185 is structurally reasonable as the proton donor and that Tyr281 is close to Glu185. Glu224 is, however, far from the catalytic site, which is inconsistent with the decreased activity exhibited by E224A. The structural flexibility of Glu224 and its neighboring residues observed in SPH1045-C may indicate that this region is able to change its conformation upon substrate binding.

    DOI: 10.1002/jobm.200900249

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  • Crystallization and preliminary crystallographic analysis of the cell-surface alginate-binding protein Algp7 isolated from Sphingomonas sp A1 査読

    Wataru Hashimoto, Akihito Ochiai, Jinshan He, Takafumi Itoh, Bunzo Mikami, Kousaku Murata

    ACTA CRYSTALLOGRAPHICA SECTION F-STRUCTURAL BIOLOGY AND CRYSTALLIZATION COMMUNICATIONS   65 ( Pt 5 )   515 - 517   2009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)   出版者・発行元:WILEY-BLACKWELL PUBLISHING, INC  

    Sphingomonas sp. A1, a Gram-negative bacterium, directly internalizes alginate macromolecules through a mouth-like pit that is present on its cell surface. The alginate-binding protein Algp7, which was found to be localized on the cell surface, contributes to the accumulation of alginate in the pit. Algp7 was crystallized at 293 K by means of the sitting- drop vapour-diffusion method with polyethylene glycol 3350 as a crystallizing agent. Preliminary X-ray analysis showed that the Algp7 crystal belonged to space group P2(1)2(1)2(1), with unit-cell parameters a = 50.1, b = 98.0, c = 100.1 angstrom, and that it diffracted to 2.8 angstrom resolution.

    DOI: 10.1107/S1744309109013669

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  • Structural Determinants Responsible for Substrate Recognition and Mode of Action in Family 11 Polysaccharide Lyases 査読

    Akihito Ochiai, Takafumi Itoh, Bunzo Mikami, Wataru Hashimoto, Kousaku Murata

    JOURNAL OF BIOLOGICAL CHEMISTRY   284 ( 15 )   10181 - 10189   2009年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC  

    A saprophytic Bacillus subtilis secretes two types of rhamnogalacturonan (RG) lyases, endotype YesW and exotype YesX, which are responsible for an initial cleavage of the RG type I (RG-I) region of plant cell wall pectin. Polysaccharide lyase family 11 YesW and YesX with a significant sequence identity (67.8%) cleave glycoside bonds between rhamnose and galacturonic acid residues in RG-I through a beta-elimination reaction. Here we show the structural determinants for substrate recognition and the mode of action in polysaccharide lyase family 11 lyases. The crystal structures of YesW in complex with rhamnose and ligand-free YesX were determined at 1.32 and 1.65 A resolution, respectively. The YesW amino acid residues such as Asn(152), Asp(172), Asn(532), Gly(533), Thr(534), and Tyr(595) in the active cleft bind to rhamnose molecules through hydrogen bonds and van der Waals contacts. Other rhamnose molecules are accommodated at the noncatalytic domain far from the active cleft, revealing that the domain possibly functions as a novel carbohydrate-binding module. A structural comparison between YesW and YesX indicates that a specific loop in YesX for recognizing the terminal saccharide molecule sterically inhibits penetration of the polymer over the active cleft. The loop-deficient YesX mutant exhibits YesW-like endotype activity, demonstrating that molecular conversion regarding the mode of action is achieved by the addition/removal of the loop for recognizing the terminal saccharide. This is the first report on a structural insight into RG-I recognition and molecular conversion of exotype to endotype in polysaccharide lyases.

    DOI: 10.1074/jbc.M807799200

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  • Crystal structure of the glycosidase family 73 peptidoglycan hydrolase FlgJ 査読

    Wataru Hashimoto, Akihito Ochiai, Keiko Momma, Takafumi Itoh, Bunzo Mikami, Yukie Maruyama, Kousaku Murata

    BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS   381 ( 1 )   16 - 21   2009年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ACADEMIC PRESS INC ELSEVIER SCIENCE  

    Glycoside hydrolase (GH) categorized into family 73 plays an important role in degrading bacterial cell wall peptidoglycan. The flagellar protein FlgJ contains N- and C-terminal domains responsible for flagellar rod assembly and peptidoglycan hydrolysis, respectively. A member of family GH-73, the C-terminal domain (SPH1045-C) of FlgJ from Sphingomonas sp. strain A1 was expressed in Escherichia coli, purified, and characterized. SPH1045-C exhibited bacterial cell lytic activity most efficiently at pH 6.0 and 37 degrees C. The X-ray crystallographic structure of SPH1045-C was determined at 1.74 angstrom resolution by single-wavelength anomalous diffraction. The enzyme consists of two lobes, a and p. A deep cleft located between the two lobes can accommodate polymer molecules, suggesting that the active site is located in the cleft. Although SPH1045-C shows a structural homology with family GH-22 and GH-23 lysozymes, the arrangement of the nucleophile/base residue in the active site is specific to each peptidoglycan hydrolase. (C) 2009 Elsevier Inc. All rights reserved.

    DOI: 10.1016/j.bbrc.2009.01.186

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  • A putative lipoprotein of Sphingomonas sp strain A1 binds alginate rather than a lipid moiety 査読

    Jinshan He, Akihito Ochiai, Yasuki Fukuda, Wataru Hashimoto, Kousaku Murata

    FEMS MICROBIOLOGY LETTERS   288 ( 2 )   221 - 226   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)   出版者・発行元:OXFORD UNIV PRESS  

    Gram-negative Sphingomonas sp. strain A1 accumulates alginate in the cell surface pit and directly incorporates the polysaccharide into its cytoplasm through a 'superchannel'. A cell surface protein Algp7 (27 kDa) is inducibly expressed in the presence of alginate. Although the protein Algp7 was initially classified as a lipoprotein based on its primary structure, Algp7 purified from strain A1 cells did not possess a lipid moiety. Algp7 bound alginate efficiently at a neutral pH with a K-d of 3.6 x 10(-8) M, suggesting that the cell surface protein contributed to accumulation of alginate in the pit.

    DOI: 10.1111/j.1574-6968.2008.01354.x

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  • A novel structural fold in polysaccharide lyases: Bacillus subtilis family 11 rhamnogalacturonan lyase YesW with an eight-bladed β-propeller 査読

    Ochiai, A, Itoh, T, Maruyama, Y, Kawamata, A, Mikami, B, Hashimoto, W, Murata, K

    Journal of Biological Chemistry   282 ( 51 )   37134 - 37145   2007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)  

    DOI: 10.1074/jbc.M704663200

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  • Plant cell wall degradation by saprophytic Bacillus subtilis strains: Gene clusters responsible for rhamnogalacturonan depolymerization 査読

    Akihito Ochiai, Takafumi Itoh, Akiko Kawamata, Wataru Hashimoto, Kousaku Murata

    APPLIED AND ENVIRONMENTAL MICROBIOLOGY   73 ( 12 )   3803 - 3813   2007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)   出版者・発行元:AMER SOC MICROBIOLOGY  

    Plant cell wall degradation is a premier event when Bacillus subtilis, a typical saprophytic bacterium, invades plants. Here we show the degradation system of rhamnogalacturonan type I (RG-I), a component of pectin from the plant cell wall, in B. subtilis strain 168. Strain 168 cells showed a significant growth on plant cell wall polysaccharides such as pectin, polygalacturonan, and RG-I as a carbon source. DNA microarray analysis indicated that three gene clusters (yesOPQRSTUVWXYZ, ytePQRST, and ybcMOPST-ybdABDE) are inducibly expressed in strain 168 cells grown on RG-I. Cells of an industrially important bacterium, B. subtilis strain natto, fermenting soybeans also express the gene cluster including the yes series during the assimilation of soybean used as a carbon source. Among proteins encoded in the yes cluster, YesW and YesX were found to be novel types of RG lyases releasing disaccharide from RG-I. Genetic and enzymatic properties of YesW and YesX suggest that strain 168 cells secrete YesW, which catalyzes the initial cleavage of the RG-I main chain, and the resultant oligosaccharides are converted to disaccharides through the extracellular exotype YesX reaction. The disaccharide is finally degraded into its constituent monosaccharides through the reaction of intracellular unsaturated galacturonyl hydrolases YesR and YteR. This enzymatic route for RG-I degradation in strain 168 differs significantly from that in plant-pathogenic fungus Aspergillus aculeatus. This is, to our knowledge, the first report on the bacterial system for complete RG-I main chain degradation.

    DOI: 10.1128/AEM.00147-07

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  • A biosystem for alginate metabolism in Agrobacterium tumefaciens strain C58: Molecular identification of Atu3025 as an exotype family PL-15 alginate lyase 査読

    Akihito Ochiai, Wataru Hashimoto, Kousaku Murata

    RESEARCH IN MICROBIOLOGY   157 ( 7 )   642 - 649   2006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)   出版者・発行元:ELSEVIER SCIENCE BV  

    The Gram-negative bacterium Sphingomonas sp. strain A I (strain A 1) has a peculiar biosystem to directly import and depolymerize a macromolecule, alginate, which is encoded by a cluster of genes on the genome. We identified five clustered ORFs homologous to some genes of the strain Al cluster in the genome of Agrobacterium tumefaciens strain C58 (strain C58). These ORFs are Atu3021, Am3022, Atu3023, and Atu3024, encoding a putative sugar ABC transporter system and Atu3025, which encodes a putative alginate lyase. We analyzed the involvement of this gene cluster in alginate metabolism. Strain C58 cells grew significantly on low-molecular-weight (LMW) alginate (average molecular weight, 1000), and we detected specific alginate-induced expression of Atu3024 and Atu3025. This strain does not grow on alginate (average molecular weight, 25 600), suggesting that the strain C58 gene cluster is involved in importing and degrading LMW alginate. One protein, Atu3025, purified from strain C58, was identified as an alginate lyase, and the enzyme overexpressed in Escherichia coli was further characterized. Atu3025 released monosaccharides specifically from alginate most efficiently at pH 7.3 and 30 degrees C through a beta-elimination reaction, indicating that Atu3025 is an exotype alginate lyase potentially involved in the assimilation of LMW alginate in strain C58. (c) 2006 Elsevier SAS. All rights reserved.

    DOI: 10.1016/j.resmic.2006.02.006

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  • Structure of unsaturated rhamnogalacturonyl hydrolase complexed with substrate 査読

    Takafumi Toh, Akihito Ochiai, Bunzo Mikami, Wataru Hashimoto, Kousaku Murata

    BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS   347 ( 4 )   1021 - 1029   2006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)   出版者・発行元:ACADEMIC PRESS INC ELSEVIER SCIENCE  

    Bacillus subtilis strain 168 YteR has been identified as a novel enzyme "unsaturated rhamnogalacturonyl hydrolase" classified in glycoside hydrolase family 105. This enzyme acts specifically on unsaturated rhamnogalacturonan (RG) produced from plant cell wall RG type-I treated with RG lyases, releasing unsaturated galacturonic acid (Delta GalA) from the substrate. The most likely candidate catalytic residue is Asp-143. Here, we show the structure of D143N in complex with unsaturated RG disaccharide (substrate) determined at 1.9 angstrom resolution by X-ray crystallography. This structural feature directly contributes to the postulation of the enzyme reaction mechanism. YteR triggers the hydration of vinyl ether group in Delta GalA, but not of glycoside bond, by using Asp-143 as a general acid and base catalyst. Asp-143 donates proton to the double bond of Delta GalA as an acid catalyst and also deprotonates a water molecule as a base catalyst. Deprotonated water molecule attacks the C5 atom of Delta GalA. (c) 2006 Elsevier Inc. All rights reserved.

    DOI: 10.1016/j.bbrc.2006.07.034

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  • A novel glycoside hydrolase family 105: The structure of family 105 unsaturated rhamnogalacturonyl hydrolase complexed with a disaccharide in comparison with family 88 enzyme complexed with the disaccharide 査読

    Takafumi Itoh, Akihito Ochiai, Bunzo Mikami, Wataru Hashimoto, Kousaku Murata

    JOURNAL OF MOLECULAR BIOLOGY   360 ( 3 )   573 - 585   2006年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD  

    YteR, a hypothetical protein with unknown functions, is derived from Bacillus subtilis strain 168 and has an overall structure similar to that of bacterial unsaturated glucuronyl hydrolase (UGL), although it exhibits little amino acid sequence identity with UGL. UGL releases unsaturated glucuronic acid from glycosaminoglycan treated with glycosaminoglycan lyases. The amino acid sequence of YteR shows a significant homology (26% identity) with the hypothetical protein YesR also from B. subtilis strain 168. To clarify the intrinsic functions of YteR and YesR, both proteins were overexpressed in Escherichia coli, purified, and characterized. Based on their gene arrangements in genome and enzyme properties, YteR and YesR were found to constitute a novel enzyme activity, "unsaturated rhamnogalacturonyl hydrolase," classified as new glycoside hydrolase family 105. This enzyme acts specifically on unsaturated rhamnogalacturonan (RG) obtained from RG type-l treated with RG lyases and releases an unsaturated galacturonic acid. The crystal structure of YteR complexed with unsaturated chondroitin disaccharide (UGL substrate) was obtained and compared to the structure of UGL complexed with the same disaccharide. The UGL substrate is sterically hindered with the active pocket of YteR. The protruding loop of YteR prevents the UGL substrate from being bound effectively. The most likely candidate catalytic residues for general acid/ base are Asp143 in YteR and Asp135 in YesR. This is supported by three-dimensional structural and site-directed mutagenesis studies. These findings provide molecular insights into novel enzyme catalysis and sequential reaction mechanisms involved in RG-I depolymerization by bacteria. (c) 2006 Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.jmb.2006.04.047

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  • Crystallization and preliminary X-ray analysis of an exotype alginate lyase Atu3025 from Agrobacterium tumefaciens strain C58, a member of polysaccharide lyase family 15 査読

    Akihito Ochiai, Masayuki Yamasaki, Bunzo Mikami, Wataru Hashimoto, Kousaku Murata

    Acta Crystallographica Section F: Structural Biology and Crystallization Communications   62 ( 5 )   486 - 488   2006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)  

    Almost all alginate lyases depolymerize alginate in an endolytical fashion via a β-elimination reaction. The alginate lyase Atu3025 from Agrobacterium tumefaciens strain C58, consisting of 776 amino-acid residues, is a novel exotype alginate lyase classified into polysaccharide lyase family 15. The enzyme was crystallized at 293 K by sitting-drop vapour diffusion with polyethylene glycol 4000 as a precipitant. Preliminary X-ray analysis showed that the Atu3025 crystal belonged to space group P21 and diffracted to 2.8 Å resolution, with unit-cell parameters a = 107.7, b = 108.3, c = 149.5 Å, β= 91.5°. © 2006 International Union of Crystallography. All rights reserved.

    DOI: 10.1107/S1744309106014333

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  • Crystallization and preliminary X-ray analysis of the rhamnogalacturonan lyase YesW from Bacillus subtilis strain 168, a member of polysaccharide lyase family 11 査読

    A Ochiai, M Yamasaki, T Itoh, B Mikami, W Hashimoto, K Murata

    ACTA CRYSTALLOGRAPHICA SECTION F-STRUCTURAL BIOLOGY AND CRYSTALLIZATION COMMUNICATIONS   62 ( Pt 5 )   438 - 440   2006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)   出版者・発行元:BLACKWELL PUBLISHING  

    Rhamnogalacturonan lyases degrade rhamnogalacturonan I, a major component of pectin, through a beta-elimination reaction. YesW from Bacillus subtilis strain 168 is a novel rhamnogalacturonan lyase classified into polysaccharide lyase family 11 (PL-11). The enzyme was crystallized at 293 K using the sitting-drop vapour-diffusion method with 2-methyl-2,4-pentanediol (MPD) as a precipitant. Preliminary X-ray analysis revealed that the YesW crystals belong to space group P2(1) and diffract to 2.40 angstrom resolution, with unit-cell parameters a = 56.7, b = 105.6, c = 101.4 angstrom, beta = 94.9 degrees. This is the first report on the crystallization and preliminary X-ray analysis of a family PL-11 rhamnogalacturonan lyase.

    DOI: 10.1107/S1744309106011894

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  • Crystallization and preliminary X-ray analysis of an exotype alginate lyase Atu3025 from Agrobacterium tumefaciens strain C58, a member of polysaccharide lyase family 15 査読

    A Ochiai, M Yamasaki, B Mikami, W Hashimoto, K Murata

    ACTA CRYSTALLOGRAPHICA SECTION F-STRUCTURAL BIOLOGY COMMUNICATIONS   62 ( Pt 5 )   486 - 488   2006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)   出版者・発行元:INT UNION CRYSTALLOGRAPHY  

    Almost all alginate lyases depolymerize alginate in an endolytical fashion via a beta-elimination reaction. The alginate lyase Atu3025 from Agrobacterium tumefaciens strain C58, consisting of 776 amino-acid residues, is a novel exotype alginate lyase classified into polysaccharide lyase family 15. The enzyme was crystallized at 293 K by sitting-drop vapour diffusion with polyethylene glycol 4000 as a precipitant. Preliminary X-ray analysis showed that the Atu3025 crystal belonged to space group P2(1) and diffracted to 2.8 angstrom resolution, with unitcell parameters a = 107.7, b = 108.3, c = 149.5 angstrom, beta = 91.5 degrees.

    DOI: 10.1107/S1744309106014333

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  • Molecular identification of Sphingomonas sp. A1 alginate lyase (A1-IV’) as a member of novel polysaccharide lyase family 15 and implications in alginate lyase evolution 査読

    Hashimoto, W, Miyake, O, Ochiai, A, Murata, K

    Journal of Bioscience and Bioengineering   99 ( 1 )   48 - 54   2005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)  

    DOI: 10.1263/jbb.99.048

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  • Overexpression, purification, and characterization of ATP-NAD kinase of Sphingomonas sp A1 査読

    A Ochiai, S Mori, S Kawai, K Murata

    PROTEIN EXPRESSION AND PURIFICATION   36 ( 1 )   124 - 130   2004年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ACADEMIC PRESS INC ELSEVIER SCIENCE  

    The NAD kinase gene (nadK) of Sphingomonas sp. A1 was cloned and then overexpressed in Escherichia coli, and the gene product (NadK) was purified from the E coli cells through five steps with a 25% yield of activity. NadK was a homodimer of 32 kDa subunits, utilized ATP or other nucleoside triphosphates, but not inorganic polyphosphates, as phosphoryl donors for the phosphorylation of NAD, most efficiently at pH 8.0 and 50-55 degreesC, and was designated as ATP-NAD kinase (NadK). NadK showed no NADH kinase activity and was slightly inhibited by NADP(H). Precursors for NAD biosynthesis such as quinolinic acid, nicotinic acid mononucleotide, nicotinic acid adenine dinucleotide, and nicotinic acid had no effect on the NadK activity, as observed in the cases of the NAD kinases of Micrococcus flavus, Mycobacterium tuberculosis, and E coli. Taken together with the report that the NAD kinase of Bacillus subtilis is activated by quinolinic acid [J. Bacteriol. 185 (2003) 4844], it is indicated that the regulatory patterns of NAD kinases differ even among bacterial NAD kinases. (C) 2004 Elsevier Inc. All rights reserved.

    DOI: 10.1016/j.pep.2004.03.012

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  • Origin and diversity of alginate lyases of families PL-5 and-7 in Sphingomonas sp strain A1 査読

    O Miyake, A Ochiai, W Hashimoto, K Murata

    JOURNAL OF BACTERIOLOGY   186 ( 9 )   2891 - 2896   2004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)   出版者・発行元:AMER SOC MICROBIOLOGY  

    Sphingonionas sp. strain A1 has three endotype alginate lyases (A1-1, A1-II [family PL-7], and A1-III [family PL-5]), each of which is encoded by a single gene. In addition to those of these lyases, a gene (the A1-II' gene) showing significant identity with the A1-II gene was present in the bacterial genome and coded for an alginate lyase with broad substrate specificity. Since no expression of A1-II' was observed even in bacterial cells grown on alginate, the A1-II' gene was thought to be a silent gene derived from the A1-II gene, presumably through duplication, modification, and translocation.

    DOI: 10.1128/JB.186.9.2891-2891.2004

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  • 天然系抗菌・防カビ剤の開発と応用

    落合秋人( 担当: 共著)

    シーエムシー出版  2019年4月 

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  • 抗菌ペプチドの機能解明と利用技術

    谷口正之, 落合秋人( 担当: 共著)

    シーエムシー出版  2017年5月 

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  • 機能性ペプチドの開発最前線

    谷口正之, 落合秋人( 担当: 共著)

    シーエムシー出版  2015年4月 

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    記述言語:日本語 著書種別:学術書

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  • 納豆に含まれるカチオン性ペプチドは内毒素中和活性と血管新生促進活性を発揮する

    谷口 正之, 落合 秋人

    ニューフードインダストリー   61 ( 8 )   577 - 588   2019年8月

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  • Novel molecular and cell biological insights into function of rice α-amylase 査読

    T. Mitsui, A. Ochiai, H. Yamakawa, K. Kaneko, A. Kitajima-Koga, M. Baslam

    Amylase   2   30 - 38   2018年8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)  

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  • 「クリプタイドを内在するヒト唾液高プロリンタンパク質P‐Bの発現様式の解析」

    斎藤英一, 相田涼介, 今井あかね, 加藤哲男, 落合秋人, 谷口正之

    日本病態プロテアーゼ学会学術集会プログラム抄録集   23rd   31   2018年

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    記述言語:日本語  

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  • コメ糠タンパク質の酵素加水分解物中のカチオン性ペプチドは多彩な生理(抗菌・LPS中和・血管新生促進)活性を発揮する抗炎症・をの多機能性

    谷口正之, 落合秋人, 山中 崇, 築野卓夫

    ニューフードインダストリー   59 ( 9 )   8 - 18   2017年9月

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    記述言語:日本語   掲載種別:記事・総説・解説・論説等(大学・研究所紀要)  

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  • Characterization and production of multifunctional cationic peptides derived from rice proteins 査読

    Masayuki Taniguchi, Akihito Ochiai

    BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY   81 ( 4 )   634 - 650   2017年4月

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    記述言語:英語   掲載種別:書評論文,書評,文献紹介等   出版者・発行元:TAYLOR & FRANCIS LTD  

    Food proteins have been identified as a source of bioactive peptides. These peptides are inactive within the sequence of the parent protein and must be released during gastrointestinal digestion, fermentation, or food processing. Of bioactive peptides, multifunctional cationic peptides are more useful than other peptides that have specific activity in promotion of health and/or the treatment of diseases. We have identified and characterized cationic peptides from rice enzymes and proteins that possess multiple functions, including antimicrobial, endotoxin-neutralizing, arginine gingipain-inhibitory, and/or angiogenic activities. In particular, we have elucidated the contribution of cationic amino acids (arginine and lysine) in the peptides to their bioactivities. Further, we have discussed the critical parameters, particularly proteinase preparations and fractionation or purification, in the enzymatic hydrolysis process for producing bioactive peptides from food proteins. Using an ampholyte-free isoelectric focusing (autofocusing) technique as a tool for fractionation, we successfully prepared fractions containing cationic peptides with multiple functions.

    DOI: 10.1080/09168451.2016.1277944

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  • オピオルフィン(エンケファリナーゼインヒビター)を内在する唾液高プロリンタンパク質の研究

    斎藤英一, 今井あかね, 加藤哲男, 落合秋人, 谷口正之

    日本病態プロテアーゼ学会学術集会プログラム抄録集   22nd   41   2017年

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    記述言語:日本語  

    J-GLOBAL

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  • コメタンパク質由来抗菌ペプチドは抗炎症作用を発揮する

    谷口正之, 落合秋人

    ニューフードインダストリー   58 ( 8 )   9 - 16   2016年8月

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    記述言語:日本語   掲載種別:記事・総説・解説・論説等(大学・研究所紀要)  

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  • ヒト全唾液中における高プロリンタンパク質P‐B(SMR3B)バリアント(Q504X8)の同定

    瀬賀拓哉, 今井あかね, 伊勢村知子, 加藤哲男, 落合秋人, 谷口正之, 斎藤英一

    日本生化学会大会(Web)   89th   ROMBUNNO.1P‐087 (WEB ONLY)   2016年

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    記述言語:日本語  

    J-GLOBAL

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  • イネ由来α-アミラーゼの立体構造とその多機能性の解析 招待

    落合秋人, 谷口正之, 三ツ井敏明

    応用糖質科学   5 ( 3 )   162 - 165   2015年8月

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    記述言語:日本語   掲載種別:記事・総説・解説・論説等(学術雑誌)  

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  • 玄米抽出液及び玄米人工消化液に含まれるフィチン酸(IP6)は、β-セクレターゼ1(BACE 1)活性を阻害する

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    ニューフードインダストリー   56 ( 9 )   45 - 53   2014年9月

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    記述言語:日本語   掲載種別:記事・総説・解説・論説等(大学・研究所紀要)  

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  • 抗生物質〜細菌との飽くなき戦い

    落合秋人

    生物工学会誌   91 ( 7 )   398   2013年7月

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    記述言語:日本語   掲載種別:記事・総説・解説・論説等(学術雑誌)   出版者・発行元:日本生物工学会  

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  • P-220 イネ由来熱ショックタンパク質Hsp70の構造と機能の解析(植物細胞工学,組織培養,育種工学,一般講演)

    菅井 寛, 落合 秋人, 原田 計, 田中 孝明, 谷口 正之

    日本生物工学会大会講演要旨集   65   243 - 243   2013年

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    記述言語:日本語   出版者・発行元:日本生物工学会  

    CiNii Article

    CiNii Books

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  • スフィンゴモナスは優等生

    落合秋人

    生物工学会誌   89 ( 10 )   614   2011年10月

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    記述言語:日本語   掲載種別:記事・総説・解説・論説等(学術雑誌)   出版者・発行元:日本生物工学会  

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  • 日本ウナギ表皮粘液の塩基性システインプロテアーゼ阻害剤の同定

    五十嵐洸陽, 笠原仁, 大滝俊樹, 大久保健介, 落合秋人, 谷口正之, 斎藤英一

    生化学   ROMBUNNO.4P-0165   2011年

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    記述言語:日本語  

    J-GLOBAL

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  • アルギン酸代謝酵素の構造と機能

    落合 秋人, 高瀬 隆一, 三上 文三, 橋本 渉, 村田 幸作

    Vitamins   84 ( 11 )   525 - 531   2010年11月

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    記述言語:日本語   掲載種別:記事・総説・解説・論説等(学術雑誌)   出版者・発行元:The Vitamin Society of Japan  

    DOI: 10.20632/vso.84.11_525

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  • 結核菌NADキナーゼの高次構造決定と機能との相関

    森茂太郎, 河井重幸, 落合秋人, 三上文三, 村田幸作

    日本農芸化学会関西支部講演会講演要旨集   2003   55   2003年10月

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受賞

  • 農芸化学奨励賞

    2020年3月   日本農芸化学会   食品タンパク質の新機能の発見とその多面的利用への構造論的展開

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  • 2017年度日本生物工学会生物工学論文賞

    2017年9月   日本生物工学会   AmyI-1–18, a cationic α-helical antimicrobial octadecapeptide derived from α-amylase in rice, inhibits the translation and folding processes in a protein synthesis system

    M. Taniguchi, A. Ochiai, S. Fukuda, T. Sato, E. Saitoh, T. Kato, T. Tanaka

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  • Award for Excellence to Authors Publishing in Bioscience, Biotechnology, and Biochemistry in 2014

    2015年3月   日本農芸化学会  

    A. Ochiai, H. Sugai, K. Harada, S. Tanaka, Y. Ishiyama, K. Ito, T. Tanaka, T. Uchiumi, M. Taniguchi, T. Mitsui

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    受賞区分:学会誌・学術雑誌による顕彰  受賞国:日本国

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共同研究・競争的資金等の研究

  • 多機能性タンパク質を用いた歯周病治療法の開発に向けた基盤構築

    2017年4月 - 2020年3月

    日本学術振興会  科学研究費助成事業  基盤研究(C)

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    資金種別:競争的資金

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  • X線結晶構造解析によるイネ由来生理活性タンパク質の機能発現に関わる分子機構の解明

    2014年4月 - 2017年3月

    日本学術振興会  科学研究費助成事業  若手研究(B)

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    資金種別:競争的資金

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  • イネ由来新規抗菌タンパク質の生理学的・構造生物学的解析

    2012年4月 - 2014年3月

    日本学術振興会  科学研究費助成事業  若手研究(B)

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    資金種別:競争的資金

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  • 歯周病予防を目指した安全な米由来抗菌タンパク質成分の探索

    2011年8月 - 2012年3月

    独立法人 科学技術振興機構  受託研究(一般受託研究) 

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    資金種別:競争的資金

    配分額:170円

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  • 植物枯死体の細胞壁分解に関わるバチルス属細菌酵素の構造生物学

    2007年4月 - 2009年3月

    科学研究費助成事業  特別研究員奨励費

      詳細を見る

    資金種別:競争的資金

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  • 生物機能工学

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  • 材料科学実験II

    2019年
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  • リメディアル演習

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  • 工業生化学

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  • 工学リテラシー入門(化学材料分野)

    2017年
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  • 生体分子工学

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    機関名:新潟大学

  • 材料科学概論

    2017年
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    機関名:新潟大学

  • 機能材料工学実験III

    2011年
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    機関名:新潟大学

  • 材料開発工学演習

    2011年
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    機関名:新潟大学

  • 卒業研究

    2010年
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    機関名:新潟大学

  • 技術英語

    2010年
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    機関名:新潟大学

  • 化学実験

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    機関名:新潟大学

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  • 工学リテラシー入門(機能材料工学科)

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  • 機能材料工学実験IV

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