Hefei National Laboratory for Physical Sciences at the Microscale and Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
Sci Adv. 2019 Mar 20;5(3):eaau6885. doi: 10.1126/sciadv.aau6885. eCollection 2019 Mar.
Most membrane proteins exist in complexes that carry out critical cellular functions and exhibit rich dynamics. The bacterial flagellar motor, a large membrane-spanning ion-driven rotary motor that propels the bacteria to swim, provides a canonical example. Rotation of the motor is driven by multiple torque-generating units (stators). Turnover of the stators has been shown previously, demonstrating the exchange of stator units between the motor and a membrane pool. But the details of the turnover kinetics remain unclear. Here, we directly measured the kinetics of stator turnover in individual motors via analysis of a large dataset of long-term high-resolution recordings of motor speed at high load. We found that the dwell time distribution of the stator units exhibits a multi-exponential shape, suggesting the existence of a hidden state in the turnover of the stators.
大多数膜蛋白存在于执行关键细胞功能并表现出丰富动力学的复合物中。细菌鞭毛马达是一种大型跨膜离子驱动的旋转马达，可推动细菌游动，它提供了一个典型的例子。马达的旋转由多个产生扭矩的单元（定子）驱动。先前已经证明了定子的周转，表明了定子单元在马达和膜池之间的交换。但是周转动力学的细节仍然不清楚。在这里，我们通过分析大量高负载下马达速度的长期高分辨率记录数据集，直接测量了单个马达中定子周转的动力学。我们发现定子单元的停留时间分布呈多指数形状，表明定子周转中存在隐藏状态。
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