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bioRxiv · 10.1101/553289

In situ structures of periplasmic flagella in Borrelia reveals conformational changes essential for flagellar rotation

Liu, J.·Chang, Y.·Moon, K.·Zhao, X.·Norris, S. J.·Motaleb, M. A.
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Abstract

The bacterial flagellar motor is a molecular machine that rotates the flagellar filament at high speed. Torque is generated by the stator-rotor interaction coupled to 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 analysis of the motor structures of wild-type and stator mutants, we localize the torque-generating units precisely and determine three-dimensional structure of the stator and its interactions with the rotor. Our study shows that the cytoplasmic domains of the stator are packed regularly around the circumference of the flagellar C-ring. The stator-rotor interaction induces a profound conformational change in the C-ring. Analysis of the motors of a less motile motB-D24E mutant and a non-motile motB-D24N mutant, in which the proton translocation is reduced and blocked, respectively, provides evidence that the conformational change of the C-ring is essential for flagellar rotation.

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Liu, J., Chang, Y., Moon, K., Zhao, X., Norris, S. J., Motaleb, M. A.. 2019-02-18. In situ structures of periplasmic flagella in Borrelia reveals conformational changes essential for flagellar rotation. https://doi.org/10.1101/553289

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