细菌鞭毛马达(BFM)是嵌入许多细菌的细胞膜中的旋转分子马达。它使鞭毛变成螺旋桨,使细菌运动和趋化性。BFM由定子单元旋转,以取决于机械和电化学环境的速率与单个马达随机缔合和解离的内膜蛋白复合物。定子单元消耗离子原动力(IMF),细胞呼吸产生的跨内膜的电化学梯度,将易位离子的电化学能转化为机械能,传递给转子。这里,我们回顾了一些主要结果,这些结果构成了我们目前对IMF与鞭毛马达功能之间关系的理解的基础。我们研究了一系列研究,这些研究建立了IMF和电机速度之间的线性比例关系,我们讨论了最近的证据,证明定子单位感知到国际货币基金组织,改变他们的动态装配率。这个,反过来,提出了一个问题,即电动机速度对IMF的经典依赖性在多大程度上是由于定子动力学与离子流通过定子的速度。最后,虽然长期以来被认为是静态和均匀的,越来越多的证据表明国际货币基金组织是动态的,并且它的波动控制着重要的现象,例如细胞间信号传导和机械转导。在不断增长的单细胞细菌电生理学工具箱中,调查国际货币基金组织波动的最佳工具之一可能是,讽刺的是,是消耗它的马达。完善我们对BFM如何利用离子流能量的不完全理解将有助于破译细菌IMF的动力学行为。
The bacterial flagellar motor (BFM) is a rotary molecular motor embedded in the cell membrane of numerous bacteria. It turns a flagellum which acts as a propeller, enabling bacterial motility and chemotaxis. The BFM is rotated by stator units, inner membrane protein complexes that stochastically associate to and dissociate from individual motors at a rate which depends on the mechanical and electrochemical environment. Stator units consume the ion motive force (IMF), the electrochemical gradient across the inner membrane that results from cellular respiration, converting the electrochemical energy of translocated ions into mechanical energy, imparted to the rotor. Here, we review some of the main results that form the base of our current understanding of the relationship between the IMF and the functioning of the flagellar motor. We examine a series of studies that establish a linear proportionality between IMF and motor speed, and we discuss more recent evidence that the stator units sense the IMF, altering their rates of dynamic assembly. This, in turn, raises the question of to what degree the classical dependence of motor speed on IMF is due to stator dynamics vs. the rate of ion flow through the stators. Finally, while long assumed to be static and homogeneous, there is mounting evidence that the IMF is dynamic, and that its fluctuations control important phenomena such as cell-to-cell signaling and mechanotransduction. Within the growing toolbox of single cell bacterial electrophysiology, one of the best tools to probe IMF fluctuations may, ironically, be the motor that consumes it. Perfecting our incomplete understanding of how the BFM employs the energy of ion flow will help decipher the dynamical behavior of the bacterial IMF.