Tan Jiaxing, Zhang Xing, Wang Xiaofei, Xu Caihuang, Chang Shenghai, Wu Hangjun, Wang Ting, Liang Huihui, Gao Haichun, Zhou Yan, Zhu Yongqun
Department of Biophysics and Department of Pathology of Sir Run Run Shaw Hospital, Life Sciences Institute and School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310058, China; The MOE Key Laboratory for Biosystems Homeostasis & Protection and Zhejiang Provincial Key Laboratory of Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, Hangzhou, Zhejiang 310058, China; Institute of Microbiology, Zhejiang University, Hangzhou, Zhejiang 310058, China.
Department of Biophysics and Department of Pathology of Sir Run Run Shaw Hospital, Life Sciences Institute and School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310058, China; Center of Cryo Electron Microscopy, Zhejiang University, Hangzhou, Zhejiang 310058, China; Liangzhu Laboratory, Zhejiang University Medical Center, Hangzhou, Zhejiang 311121, China.
Cell. 2021 May 13;184(10):2665-2679.e19. doi: 10.1016/j.cell.2021.03.057. Epub 2021 Apr 20.
The bacterial flagellar motor is a supramolecular protein machine that drives rotation of the flagellum for motility, which is essential for bacterial survival in different environments and a key determinant of pathogenicity. The detailed structure of the flagellar motor remains unknown. Here we present an atomic-resolution cryoelectron microscopy (cryo-EM) structure of the bacterial flagellar motor complexed with the hook, consisting of 175 subunits with a molecular mass of approximately 6.3 MDa. The structure reveals that 10 peptides protruding from the MS ring with the FlgB and FliE subunits mediate torque transmission from the MS ring to the rod and overcome the symmetry mismatch between the rotational and helical structures in the motor. The LP ring contacts the distal rod and applies electrostatic forces to support its rotation and torque transmission to the hook. This work provides detailed molecular insights into the structure, assembly, and torque transmission mechanisms of the flagellar motor.
细菌鞭毛马达是一种超分子蛋白质机器，它驱动鞭毛旋转以实现运动，这对于细菌在不同环境中的生存至关重要，也是致病性的关键决定因素。鞭毛马达的详细结构仍然未知。在此，我们展示了与钩状体复合的细菌鞭毛马达的原子分辨率冷冻电子显微镜（cryo-EM）结构，该结构由175个亚基组成，分子量约为6.3 MDa。该结构表明，从MS环伸出的带有FlgB和FliE亚基的10个肽介导了从MS环到杆的扭矩传递，并克服了马达中旋转结构和螺旋结构之间的对称性不匹配。LP环与远端杆接触并施加静电力以支持其旋转并将扭矩传递到钩状体。这项工作为鞭毛马达的结构、组装和扭矩传递机制提供了详细的分子见解。
