Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, United States.
Microbial Sciences Institute, Yale University, West Haven, United States.
Elife. 2019 Jul 17;8:e48979. doi: 10.7554/eLife.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, . 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.
细菌鞭毛马达是一种能够高速旋转鞭毛丝的分子机器。旋转是由定子-转子相互作用产生的，同时伴随着离子通过产生扭矩的定子的流动。在这里，我们采用冷冻电镜断层扫描技术可视化了莱姆病螺旋体中的完整鞭毛马达。通过分析野生型和定子缺失突变体的马达结构，我们不仅在原位定位了定子复合物，还以前所未有的细节揭示了定子-转子相互作用。重要的是，定子-转子相互作用引起了鞭毛 C 环的构象变化。鉴于我们观察到一个不能产生类似构象变化的非运动突变体，其中质子流被阻断，我们提出质子驱动的扭矩负责产生旋转所需的构象变化。
