High-resolution structural analysis of bacterial flagellar stator complex

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K06085
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 43020:Structural biochemistry-related
• Research Institution: Chuo University (2019-2020); Osaka University (2018)
• Principal Investigator: Terahara Naoya 中央大学, 理工学部, 助教 (40554738)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: 生体分子モーター / クライオ電子顕微鏡 / 高速AFM

Outline of Final Research Achievements

A bacterial flagellar motor is a supramolecular complex that functions as a rotary motor consisting of a rotor and a stator. The energy for torque generation is mediated by an inward ion flux through the channels of the stator complex. Here, to clarify the structure of sodium-channel MotPS that acts as a Bacillus subtilis flagellar stator and its dynamic structural changes with high resolution, cryo-electron microscopy and high-speed AFM observation of the purified stator complex were carried out. We tested the chemically modified grids to achieve more effective ice embedding. More monodisperse particles were observed in one modified grid. On the other hand, high-speed AFM observation revealed that the transmembrane regions of MotPS stator complex strongly interact with the mica surface. Further improvements are necessary to control the orientation.

Free Research Field

生物物理

Academic Significance and Societal Importance of the Research Achievements

固定子がどのようにイオンの流れを回転力に変換しているのか全く不明である。固定子の高分解能構造およびその動的構造変化の情報は、べん毛モーターの回転メカニズムを明らかにする上で必須である。さらに、これらの情報はべん毛モーター研究だけでなく、生物分子モーターの動作原理の解明の一端を担う重要な研究課題として位置づけられる。そして、それらの知見は人工的な分子マシンを構築する際に多くの知見をもたらすと期待される。