2019 Fiscal Year Final Research Report

Structural feature of nobel piezophilic lipases from marine piezophilic psychrophile

Research Project

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Project/Area Number	16K07870
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Multi-year Fund
Section	一般
Research Field	Aquatic life science
Research Institution	Tokyo University of Marine Science and Technology
Principal Investigator	Ishida Masami 東京海洋大学, 学術研究院, 教授 (80223006)
Co-Investigator(Kenkyū-buntansha)	岡井公彦東京海洋大学, 学術研究院, 助教 (00596562)
Project Period (FY)	2016-04-01 – 2020-03-31
Keywords	高圧適応 / リパーゼ / プロテアーゼ / 海洋中層 / 未知遺伝子 / 遺伝子対 / 水素結合
Outline of Final Research Achievements	To investigate the high-pressure characteristics of enzymes from marine bacteria inhabit intermediate water of deep sea, we determined the structure and properties of the novel lipases Lip-I and Lip-II from Moritella sp. strains F1 and F3. The lipases showed high-pressure resistance, and they had novel structures different from those of known lipases. The genes of Lip-I and Lip-II were present adjacently on the genomes of the strains F1 and F3, as well as similar gene pairs were on genomes of other marine bacteria, suggesting a new action in cooperation of both enzymes. Secondly, we determined the structure and properties of the PR protease from Vibrio sp. strain Pr21. The protease showed highly piezophilic activity. Based on comparison between PR protease and a mutant enzyme, the hydrogen bond might affect in the increased activity under high-pressure and low-temperature conditions.
Free Research Field	海洋生化学
Academic Significance and Societal Importance of the Research Achievements	海洋中層（深度200～1,000 m）は何千mもの深海より試料採取が容易だが、微生物や酵素の資源としての価値が不明確だったので、中層由来微生物とその酵素を標的とした。リパーゼは産業的な利用価値があり、現在も新らたな酵素が探索される。本研究では、中層細菌から発見した従来の報告が全くない2種の新奇リパーゼを主な研究対象とした。遺伝子解析から2種のリパーゼが対になって働く新たな機能が示唆された。酵素の高圧適応機構の報告は非常に少ないので、中層細菌のリパーゼとプロテアーゼで構造と圧力特性の解析を目指し、プロテアーゼで、高圧下の柔軟性によって好圧性に影響する水素結合の役割を示した。