Model Studies of the Dynamics of Bacterial Flagellar Motors
Model Studies of the Dynamics of Bacterial Flagellar Motors
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DOI：
10.1016/j.bpj.2009.01.023
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发表时间：
2009-04-22
影响因子：
3.4
通讯作者：
Xing, Jianhua
中科院分区：
文献类型：
--
作者：
Bai, Fan;Lo, Chien-Jung;Xing, Jianhua
细菌鞭毛马达是一种旋转分子机器，它旋转推动游动细菌的螺旋丝。对电机的结构、装配、能量输入、发电和切换机制进行了大量的实验和理论研究。在上一篇文章中，我们用简单的两态福克-普朗克模型解释了观察到的扭矩-速度曲线下的一般物理原理。在这里，我们进一步分析该模型，表明：1）该模型预测离子动力的两个分量会对电机动力学产生不同的影响，与最新的实验一致； 2)，通过明确考虑定子弹簧，该模型还解释了最近观察到的质子电机中零负载速度对定子数量的依赖性； 3)，即使存在定子弹簧，该模型也会重现电机的步进行为并预测停留时间分布。讨论了具有两个定子的电机的预测步进行为，并建议未来的实验程序进行验证。
The bacterial flagellar motor is a rotary molecular machine that rotates the helical filaments that propel swimming bacteria. Extensive experimental and theoretical studies exist on the structure, assembly, energy input, power generation, and switching mechanism of the motor. In a previous article, we explained the general physics underneath the observed torque-speed curves with a simple two-state Fokker-Planck model. Here, we further analyze that model, showing that 1), the model predicts that the two components of the ion motive force can affect the motor dynamics differently, in agreement with latest experiments; 2), with explicit consideration of the stator spring, the model also explains the lack of dependence of the zero-load speed on stator number in the proton motor, as recently observed; and 3), the model reproduces the stepping behavior of the motor even with the existence of the stator springs and predicts the dwell-time distribution. The predicted stepping behavior of motors with two stators is discussed, and we suggest future experimental procedures for verification.