Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026, China.
Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
Proc Natl Acad Sci U S A. 2017 Nov 21;114(47):12478-12482. doi: 10.1073/pnas.1713655114. Epub 2017 Nov 6.
Rotation of the bacterial flagellar motor is driven by multiple torque-generating units (stator elements). The torque-generating dynamics can be understood in terms of the "duty ratio" of the stator elements, that is, the fraction of time a stator element engages with the rotor during its mechanochemical cycle. The dependence of the limiting speed (zero-load speed) of the motor on the number of stator elements is the determining test of the duty ratio, which has been controversial experimentally and theoretically over the past decade. Here, we developed a method combining laser dark-field microscopy and optical trapping to resolve this controversy. We found that the zero-load speed is independent of the number of stator elements for the bacterial flagellar motor in , demonstrating that these elements have a duty ratio close to 1.
细菌鞭毛马达的旋转是由多个产生扭矩的单元（定子元件）驱动的。从定子元件的“占空比”（即在其机械化学循环过程中与转子啮合的时间分数）可以理解产生扭矩的动力学。马达的极限速度（空载速度）与定子元件数量的依赖关系是占空比的决定性测试，这在过去十年的实验和理论上一直存在争议。在这里，我们开发了一种结合激光暗场显微镜和光阱的方法来解决这一争议。我们发现，在 中，细菌鞭毛马达的空载速度与定子元件的数量无关，这表明这些元件的占空比接近 1。
