Is a Hydrogenase-Like Enzyme Complex Lacking a Catalytic Center the Missing Link in the Respiratory Complexes?

2022 Fiscal Year Final Research Report

• Project/Area Number: 21K20578
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Multi-year Fund
• Review Section: 0601:Agricultural chemistry and related fields
• Research Institution: Ritsumeikan University
• Principal Investigator: Inoue Masao 立命館大学, 立命館グローバル・イノベーション研究機構, 助教 (90906976)
• Project Period (FY): 2021-08-30 – 2023-03-31
• Keywords: 呼吸鎖複合体 / ヒドロゲナーゼ / 分子進化 / 微生物ゲノム

Outline of Final Research Achievements

This project is aimed to elucidate the missing link in the molecular evolution of the [NiFe] hydrogenase/respiratory complex I enzymes, which play a fundamental role in cellular respiration from primitive organisms to humans, and to clarify the respiratory function of the hydrogenase-like enzyme complex Ehr, which has lost its NiFe active site. Bioinformatics analysis of all prokaryotic genomes revealed that Ehr is the third subfamily of respiratory complex I-type enzymes, widely conserved in environmental microorganisms and involved in electron transfer and proton transport. Moreover, we succeeded in constructing a platform to elucidate physiological functions by optimizing the culture conditions of a bacterial strain carrying this enzyme gene cluster and producing gene-knockout strain.

Free Research Field

応用微生物学

Academic Significance and Societal Importance of the Research Achievements

始原生物が有していた [NiFe] ヒドロゲナーゼが、いかにしてその活性に必須である金属活性中心を失い、NAD を補酵素とする呼吸鎖複合体 I に進化したのかは生物進化における大きな謎の 1 つであった。本研究では、呼吸鎖複合体 I とは異なる進化を遂げた第 3 の呼吸鎖複合体 I 型酵素サブファミリーの存在を世界に先駆けて明らかにすることに成功した。得られた生物情報資源は新たな研究シーズとなることが予想され、応用微生物学や進化生物学の発展に大きく貢献する。