Department of Biology, University of Utah, Salt Lake City, UT, USA.
EMBO J. 2011 Jun 14;30(14):2962-71. doi: 10.1038/emboj.2011.188.
Rotation and switching of the bacterial flagellum depends on a large rotor-mounted protein assembly composed of the proteins FliG, FliM and FliN, with FliG most directly involved in rotation. The crystal structure of a complex between the central domains of FliG and FliM, in conjunction with several biochemical and molecular-genetic experiments, reveals the arrangement of the FliG and FliM proteins in the rotor. A stoichiometric mismatch between FliG (26 subunits) and FliM (34 subunits) is explained in terms of two distinct positions for FliM: one where it binds the FliG central domain and another where it binds the FliG C-terminal domain. This architecture provides a structural framework for addressing the mechanisms of motor rotation and direction switching and for unifying the large body of data on motor performance. Recently proposed alternative models of rotor assembly, based on a subunit contact observed in crystals, are not supported by experiment.
细菌鞭毛的旋转和切换依赖于一个由 FliG、FliM 和 FliN 等蛋白组成的大型转子安装蛋白组件，其中 FliG 最直接参与旋转。FliG 中央结构域与 FliM 的复合物的晶体结构，结合了一些生化和分子遗传学实验，揭示了转子中 FliG 和 FliM 蛋白的排列方式。FliG（26 个亚基）和 FliM（34 个亚基）之间的化学计量不匹配可以用 FliM 的两个不同位置来解释：一个位置与 FliG 中央结构域结合，另一个位置与 FliG C 端结构域结合。这种结构为解决马达旋转和方向切换的机制以及统一大量关于马达性能的数据提供了一个结构框架。最近提出的基于晶体中观察到的亚基接触的替代转子组装模型，并没有得到实验的支持。
