Torque transmission mechanism of the curved bacterial flagellar hook revealed by cryo-EM.
Torque transmission mechanism of the curved bacterial flagellar hook revealed by cryo-EM.
复制标题
冷冻电镜揭示弯曲细菌鞭毛钩的扭矩传递机制。
DOI：
10.1038/s41594-019-0301-3
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发表时间：
2019
影响因子：
16.8
通讯作者：
Wolf M
中科院分区：
文献类型：
--
作者：
Shibata S;Matsunami H;Aizawa SI;Wolf M
细菌通过旋转鞭毛的运动是通过钩子实现的，钩子将扭矩从马达传递到鞭毛。钩是由单一类型的蛋白质组成的管状结构，但它采用弯曲的形状。为了发挥其功能，它必须同时具有柔性和扭转刚性。化学上相同的亚基形成这种动态结构的分子机制尚不清楚。在这里，我们显示了完整的结构，从沙门氏菌肠在其超螺旋的'弯曲'状态，在2.9倍分辨率。弯钩中的亚基分为11种不同的构象，每种构象沿沿着11条原丝共享。延长的钩亚基的结构域表现为通过两个铰链区连接的刚性体。重构模型演示了相同的亚基如何在弯曲时通过物理相互作用动态改变构象。这些多亚基状态与鞭毛多态性的关键特征--双态模型相矛盾。
Bacterial locomotion by rotating flagella is achieved through the hook, which transmits torque from the motor to the filament. The hook is a tubular structure composed of a single type of protein, yet it adopts a curved shape. To perform its function, it must be simultaneously flexible and torsionally rigid. The molecular mechanism by which chemically identical subunits form such a dynamic structure is unknown. Here, we show the complete structure of the hook fromSalmonella entericain its supercoiled ‘curved’ state, at 2.9 Å resolution. Subunits in the curved hook are grouped into 11 distinctive conformations, each shared along 11 protofilaments. The domains of the elongated hook subunit behave as rigid bodies connected by two hinge regions. The reconstituted model demonstrates how identical subunits can dynamically change conformation by physical interactions while bending. These multiple subunit states contradict the two-state model, which is a key feature of flagellar polymorphism.