Study on Structure and Function for Force Generating Mechanism of Bacterial Flagellar Motor

2023 Fiscal Year Final Research Report

• Project/Area Number: 20H03220
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 43040:Biophysics-related
• Research Institution: Nagoya University
• Principal Investigator: Homma Michio 名古屋大学, 理学研究科, 研究員 (50209342)
• Project Period (FY): 2020-04-01 – 2024-03-31
• Keywords: 生体エネルギー変換 / モータータンパク質 / べん毛

Outline of Final Research Achievements

Bacterial flagella are the only rotary locomotive organelles in the living world. A motor built in the cell membrane rotates at high speed in conjunction with ion influx. This ultra-small, high-speed nanomachine, a membrane supramolecular complex, is composed of a rotor and a stator, just like an electric motor made by us, and the torque is generated by the interaction between rotor and stator. Based on the accumulated researches done by this investigator, the structural analysis of the stator and rotor using a cryo-electron microscope and the biochemical analysis have been done and a model in which the rotor and stator generate torque by acting like protein gears was presented. In addition, a new model has been proposed in which the plug region of the stator controls ion transport by functioning like a spanner.

Free Research Field

生物物理

Academic Significance and Societal Importance of the Research Achievements

膜超分子複合体であるこの超小型高速ナノマシンは、電気モーターなどと同じく、回転子と固定子から構成されており、それらの間で回転力を発生する。イオン流がどのようにべん毛複合体の中を流れ、固定子分子と回転子分子間の相互作用が、回転エネルギーに変換されるメカニズムの解明に大きく貢献した。そして、固定子と回転子の構造と機能解析から、それらタンパク質の構造変換がどのように起こり、どのような相互作用によって回転力に変換されるのかを明らかにし、普遍的なモータータンパク質が内包するエネルギー変換に必要な構造と生命科学における普遍的な物理化学的法則の解明に大きく貢献した。