Structural study of substrate recognition mechanism of polyketide synthase

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K15746
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 38030:Applied biochemistry-related
• Research Institution: The University of Tokyo
• Principal Investigator: Nagata Ryuhei 東京大学, 大学院農学生命科学研究科(農学部), 特別研究員 (10836703)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: X線結晶構造解析 / ポリケタイド合成酵素

Outline of Final Research Achievements

We revealed the substrate-binding mechanism of a thioesterase ElbB, which is one of the domains of type I polyketide synthases, based on its crystal structures. Although the overall structure of ElbB is similar to those of other thioesterases, ElbB has no entrance at the substrate-binding pocket observed in other thioesterases. In contrast, the ElbB mutant exhibited an open form in the crystal structure. These observations let us to propose that ElbB will move to open the substrate-binding pocket and accept the substrate. In addition, docking simulation between the reaction intermediate and the ElbB structure estimated residues important for substrate binding, and we confirmed the importance of the residues by mutational analysis.

Free Research Field

構造生物学

Academic Significance and Societal Importance of the Research Achievements

I型ポリケタイド合成酵素の複数ドメイン間での基質の受け渡し機構については未解明な部分が多い。本研究では、タンパク質の細胞内輸送阻害剤として有名なbrefeldin Aの生合成に関わるチオエステル加水分解酵素ドメインについて、基質結合に伴ってポケットが開閉することを提唱した。また、コンピューターシミュレーションを用いてこの酵素の特異的な基質認識機構を明らかにした。これらの成果は、チオエステル加水分解酵素ドメインにおける基質の受け入れ機構の解明や、酵素改変によるbrefeldin A類縁体の創出につながると期待される。