2021 Fiscal Year Final Research Report
Developing crosslinkers specific for epimerization domain in initiation modules to evaluate mechanism
| Project/Area Number |
19K05722
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Review Section |
Basic Section 37020:Chemistry and chemical methodology of biomolecules-related
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| Research Institution | Kindai University |
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Principal Investigator |
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| Project Period (FY) |
2019-04-01 – 2022-03-31
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| Keywords | 非リボソームペプチド合成酵素 / 異性化酵素 / キャリアータンパク質 / 共有結合性異性化酵素阻害剤 / タンパク質間相互作用 |
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| Outline of Final Research Achievements |
Nonribosomal peptide synthetases (NRPSs) unique molecular factories can produce peptides with nonproteinogenic D-amino acids in which the epimerization (E) domain catalyzes the conversion of L-amino acids to D-amino acids, but its mechanism remains not fully understood. Here, we describe the development of pantetheine crosslinking probes that mimic the natural substrate L-Phe of the initiation module of tyrocidine synthetase, TycA, to elucidate and study the catalytic residues of the E domain. Mechanism-based crosslinking assays and MALDI-TOF MS were used to identify both H743 and E882 as the crosslinking site residues, demonstrating their roles as catalytic bases. Mutagenesis studies further validated these results and allowed the comparison of reactivity between the catalytic residues, concluding that glutamate acts as the dominant nucleophile in the crosslinking reaction, resembling the deprotonation of the Ca-H of amino acids in the epimerization reaction.
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| Free Research Field |
ケミカルバイオロジー
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| Academic Significance and Societal Importance of the Research Achievements |
本研究で開発したクロスリンク剤を利用することで, 1) 異性化酵素の触媒残基を捕捉することによる異性化機構の解明, 2) 異性化反応の瞬間を捕捉することにより, 異性化酵素とキャリアータンパク質相互作用の生化学的解析および異性化酵素とキャリアータンパク質複合体構造の結晶構造を解くこと, が可能となりペプチド系天然物の多様性の創出に関わる酵素の機能や構造が分子レベルで明らかになる. それら情報を基に合理的に生合成システムをデザインすることにより, 天然にはないペプチド系化合物の創製など応用に結びつけることができる.
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