Molecular mechanism of mechano-chemical reaction cycle in the proton-driven flagellar motor

2014 Fiscal Year Final Research Report

• Project/Area Number: 24770141
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Biophysics
• Research Institution: Tohoku University
• Principal Investigator: NAKAMURA Shuichi 東北大学, 工学(系)研究科(研究院), 助教 (90580308)
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: 分子モーター / べん毛モーター / 一分子計測 / 回転ステップ / エネルギー変換 / 細菌運動

Outline of Final Research Achievements

Bacteria can move by rotating flagella. The flagellar filament is linked with the rotary nanomachine called the flagellar motor, which is embedded in the cytoplasmic membrane. The flagellar motor consists of a rotor and stators. It is known that the proton translocation through the stator unit is converted to the mechanical work, but the energy-conversion mechanism still remains unclear. In this study, we performed a single-molecule measurement of the bacterial flagellar motor in order to elucidate the mechanism of energy conversion. Observation of a 100-nm gold nanoparticle adhered to a single flagellar filament of Salmonella showed step motions, tracks with moving and waiting periods. The step event is believed to be an elementary process of the energy-conversion reaction. Thus, our results offer important insight into the rotation mechanism of flagellar motors.

Free Research Field

生物物理学