Kitao Akio, Hata Hiroaki
School of Life Science and Technology, Tokyo Institute of Technology, M6-13, 2-12-1 Ookayama, Meguro-ku, Tokyo, 152-8550, Japan.
Institute of Molecular and Cellular Biosciences, The University of Tokyo, Tokyo, Japan.
Biophys Rev. 2018 Apr;10(2):617-629. doi: 10.1007/s12551-017-0338-7. Epub 2017 Nov 27.
The bacterial flagellum is a biological nanomachine for the locomotion of bacteria, and is seen in organisms like Salmonella and Escherichia coli. The flagellum consists of tens of thousands of protein molecules and more than 30 different kinds of proteins. The basal body of the flagellum contains a protein export apparatus and a rotary motor that is powered by ion motive force across the cytoplasmic membrane. The filament functions as a propeller whose helicity is controlled by the direction of the torque. The hook that connects the motor and filament acts as a universal joint, transmitting torque generated by the motor to different directions. This report describes the use of molecular dynamics to study the bacterial flagellum. Molecular dynamics simulation is a powerful method that permits the investigation, at atomic resolution, of the molecular mechanisms of biomolecular systems containing many proteins and solvent. When applied to the flagellum, these studies successfully unveiled the polymorphic supercoiling and transportation mechanism of the filament, the universal joint mechanism of the hook, the ion transfer mechanism of the motor stator, the flexible nature of the transport apparatus proteins, and activation of proteins involved in chemotaxis.
细菌鞭毛是一种用于细菌运动的生物纳米机器，在沙门氏菌和大肠杆菌等生物体中可见。鞭毛由数万个蛋白质分子和30多种不同的蛋白质组成。鞭毛的基体包含一个蛋白质输出装置和一个由跨细胞质膜的离子驱动力驱动的旋转马达。细丝起着螺旋桨的作用，其螺旋度由扭矩方向控制。连接马达和细丝的钩充当万向节，将马达产生的扭矩传递到不同方向。本报告描述了使用分子动力学来研究细菌鞭毛。分子动力学模拟是一种强大的方法，它允许在原子分辨率下研究包含许多蛋白质和溶剂的生物分子系统的分子机制。当应用于鞭毛时，这些研究成功揭示了细丝的多晶型超螺旋和运输机制、钩的万向节机制、马达定子的离子转移机制、运输装置蛋白质的柔性性质以及参与趋化作用的蛋白质的激活。
