Structural insights into flagellar stator–rotor interactions

• Main Authors: Yunjie Chang, Ki Hwan Moon, Xiaowei Zhao, Steven J Norris, MD A Motaleb, Jun Liu
• Format: Article
• Language: English
• Published: eLife Sciences Publications Ltd 2019-07-01
• Series: eLife
• Subjects: bacterial flagella; nanomachine; motility; spirochete; protein-protein interaction
• Online Access: https://elifesciences.org/articles/48979

The bacterial flagellar motor is a molecular machine that can rotate the flagellar filament at high speed. The rotation is generated by the stator–rotor interaction, coupled with an ion flux through the torque-generating stator. Here we employed cryo-electron tomography to visualize the intact flagellar motor in the Lyme disease spirochete, Borrelia burgdorferi. By analyzing the motor structures of wild-type and stator-deletion mutants, we not only localized the stator complex in situ, but also revealed the stator–rotor interaction at an unprecedented detail. Importantly, the stator–rotor interaction induces a conformational change in the flagella C-ring. Given our observation that a non-motile mutant, in which proton flux is blocked, cannot generate the similar conformational change, we propose that the proton-driven torque is responsible for the conformational change required for flagellar rotation.