Structure and Function of Stator Units of the Bacterial Flagellar Motor
Structure and Function of Stator Units of the Bacterial Flagellar Motor
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DOI：
10.1101/2020.05.15.096610
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发表时间：
2020-05
期刊：
影响因子：
64.5
通讯作者：
M. Santiveri;A. Roa-Eguiara;Caroline Kühne;N. Wadhwa;H. Berg;M. Erhardt;N. Taylor
中科院分区：
文献类型：
--
作者：
M. Santiveri;A. Roa-Eguiara;Caroline Kühne;N. Wadhwa;H. Berg;M. Erhardt;N. Taylor
许多细菌利用鞭毛来移动和趋化。它的双向旋转由嵌入膜的电机驱动，该电机利用来自跨膜离子梯度的能量在定子单元和转子之间的界面产生转矩。定子单元（MotAB）的结构组织，离子传输时的构象变化，以及这些变化如何驱动鞭毛旋转，仍然是未知的。在这里，我们展示了~3 Å-resolution定子单元在不同功能状态下的冷冻电子显微镜重建。我们发现定子单元由一个二聚体MotB和一个五聚体MotA组成。结合结构数据、突变和功能研究，我们确定了参与扭矩产生的关键残基，并提出了运动功能和旋转方向切换的机制模型。双向细菌鞭毛马达产生扭矩的结构基础
Many bacteria use the flagellum for locomotion and chemotaxis. Its bi-directional rotation is driven by the membrane-embedded motor, which uses energy from the transmembrane ion gradient to generate torque at the interface between stator units and rotor. The structural organization of the stator unit (MotAB), its conformational changes upon ion transport and how these changes power rotation of the flagellum, remain unknown. Here we present ~3 Å-resolution cryo-electron microscopy reconstructions of the stator unit in different functional states. We show that the stator unit consists of a dimer of MotB surrounded by a pentamer of MotA. Combining structural data with mutagenesis and functional studies, we identify key residues involved in torque generation and present a mechanistic model for motor function and switching of rotational direction. One Sentence Summary Structural basis of torque generation in the bidirectional bacterial flagellar motor