Insights into the stator assembly of the Vibrio flagellar motor from the crystal structure of MotY
Insights into the stator assembly of the Vibrio flagellar motor from the crystal structure of MotY
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DOI：
10.1073/pnas.0800308105
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发表时间：
2008-06-03
影响因子：
11.1
通讯作者：
Imada, Katsumi
中科院分区：
文献类型：
--
作者：
Kojima, Seiji;Shinohara, Akari;Imada, Katsumi
钠驱动的溶藻弧菌极鞭毛的旋转需要四种马达蛋白：PomA，PomB，MotX和MotY。PomA和PomB在细胞质膜中形成钠离子通道，其充当定子复合物以将钠离子通量与扭矩产生耦合。MotX和MotY是T环的组成部分，T环位于极鞭毛基体的P环下方，并参与将PomA/PomB复合物并入马达中。在这里，我们描述，在2.9埃分辨率的MotY的晶体结构的测定。该结构显示两个不同的结构域：N-末端结构域（MotY-N）和C-末端结构域（MotY-C）。MotY-N具有独特的结构。MotY-C含有一个假定的肽聚糖结合基序，该基序与肽聚糖结合蛋白（如RmpM和RmpM）的基序非常相似，但该区域在MotY中是无序的。产生MotY-N和MotY-C片段的细胞的运动性测定和随后的生物化学分析表明，MotY-N是转子周围定子单元的缔合所必需的，而MotY-C通过与肽聚糖层结合来稳定缔合。基于这些观察，我们提出了一个模型的机制，定子组件周围的转子。
Rotation of the sodium-driven polar flagellum of Vibrio alginolyticus requires four motor proteins: PomA, PomB, MotX, and MotY. PomA and PomB form a sodium-ion channel in the cytoplasmic membrane that functions as a stator complex to couple sodium-ion flux with torque generation. MotX and MotY are components of the T-ring, which is located beneath the P-ring of the polar flagellar basal body and is involved in incorporation of-the PomA/PomB complex into the motor. Here, we describe,the determination of the crystal structure of MotY at 2.9 angstrom resolution. The structure shows two distinct domains: an N-terminal domain (MotY-N) and a C-terminal domain (MotY-C). MotY-N has a unique structure. MotY-C contains a putative peptidoglycan-binding motif that is remarkably similar to those of peptidoglycan-binding proteins, such as Pal and RmpM, but this region is disordered in MotY. Motility assay of cells producing either of the MotY-N and MotY-C fragments and subsequent biochemical analyses indicate that MotY-N is essential for association of the stator units around the rotor, whereas MotY-C stabilizes the association by binding to the peptidoglycan layer. Based on these observations, we propose a model for the mechanism of stator assembly around the rotor.