Functional and Structural Relationship of V-ATPase Revealed by Single-Molecule Observation

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K15060
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 43040:Biophysics-related
• Research Institution: Institute for Molecular Science
• Principal Investigator: Otomo Akihiro 分子科学研究所, 生命・錯体分子科学研究領域, 助教 (30886560)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: V-ATPase / １分子観察 / ナトリウムイオンポンプ / ATP合成酵素

Outline of Final Research Achievements

To elucidate the correlation between the function and structure of rotary ATPases, I undertook obsercations of single-molecule rotation, ATP synthesis measurement, and functional conversion for the sodium-ion transporting EhV-ATPase. I successfully visualized the rotational motion of the entire EhV-ATPase complex, revealing steps associated with ion transport. A new experimental system was constructed, and for the first time, it was demonstrated that EhV-ATPase can synthesize ATP driven by the electrochemical potential of sodium ions. A comprehensive sequence comparison among ATPases allowed us to convert the function of sodium-ion transporting EhV-ATPase to proton transport. These achievements contribute to our understanding of energy conversion within living organisms.

Free Research Field

生物物理

Academic Significance and Societal Importance of the Research Achievements

回転型ATPaseは生体内エネルギー変換装置として生命科学のみならず、ナノテクノロジー分野においても重要なタンパク質である。これまで理解が不十分であった、イオン輸送部位の回転機構や機能の可逆性、イオン選択機構を明らかにした本成果は、新たな分子モーターの創生や細胞機能制御への展開が期待できる。定量的なナトリウムイオン輸送の検出やATP合成時の回転運動の可視化など今後の課題も明確になり、学術的にも意義が深い。