Mechanism of quinolone formation by hemocyanin-like enzyme cyclopenase

2020 Fiscal Year Final Research Report

• Project/Area Number: 19K15757
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 38040:Bioorganic chemistry-related
• Research Institution: University of Shizuoka
• Principal Investigator: Kishimoto Shinji 静岡県立大学, 薬学部, 助教 (40814330)
• Project Period (FY): 2019-04-01 – 2021-03-31
• Keywords: 酵素反応 / ヘム / 新規化合物

Outline of Final Research Achievements

We recently reported that hemocyanine-like enzyme cyclopenase converts cyclopenin to viridicatin. Why does cyclopenase show such activity? One reason is the difference of metal ion in active sites and another one is the heme-binding domain present only in cyclopenase. In this work, we tried to elucidate the role of heme-binding domain in cyclopenase.
Reducing the content of heme in cyclopenase AsqI clearly decreased the reaction rate but not the affinity to substrate, suggesting that heme-binding domain is not related to substrate binding. Mutation at either metal-binding domain or heme-binding domain abolished enzyme activity, however, mixture of both mutants converted cyclopenin to viridicatin. Cyclopenase from Aspergillus lentulus showed enzymatic activity despite mutation at heme-binding domain. These findings indicated that heme-binding domain is involved in regulation of cyclopenase.

Free Research Field

天然物化学

Academic Significance and Societal Importance of the Research Achievements

本研究では酸素運搬タンパク質とシクロペナーゼの違いの一つであるヘム結合ドメインがどのようにして機能しているかを明らかにするべく実験を行った。本研究期間では完全な解明には至っていないが研究を突き詰めて酵素活性の違いを生む要因を明らかにすることで、タンパク質に新しい機能を与えるための知見が得られる。これにより、将来的に望みの活性を有する新規酵素を創出できるようになると期待できる。