Torque-speed relationship of the flagellar rotary motor of Escherichia coli
Torque-speed relationship of the flagellar rotary motor of Escherichia coli
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DOI：
10.1016/s0006-3495(00)76662-8
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发表时间：
2000-02-01
影响因子：
3.4
通讯作者：
Berg, HC
中科院分区：
文献类型：
--
作者：
Chen, XB;Berg, HC
旋转电机的输出以其转矩和速度为特征。用一种新的方法测定了大肠杆菌鞭毛马达的转矩-速度关系。在弱光阱中，通过后焦平面干涉法在含有不同浓度的粘性剂Ficoll的溶液中监测球体的角速度。在三个不同温度22.7、17.7和15.8 ° C下，在宽动态范围（高达类似于300 Hz的速度）内获得相对扭矩（粘度X速度）对速度的曲线图。J. 65：2201-2216）得到证实。电动机在两种动态状态下运行。在23摄氏度时，扭矩在接近200 Hz的拐点速度下近似恒定，然后它随着速度迅速福尔斯到类似于350 Hz的零扭矩速度。在低速状态下，扭矩对温度变化不敏感。在高速区，它在较低的温度下显著降低。这些结果与动力行程机构产生扭矩的模型一致（Berry和贝格，1999年，Biophys. J，76：580-587）。
The output of a rotary motor is characterized by its torque and speed. We measured the torque-speed relationship of the flagellar rotary motor of Escherichia coli by a new method, Small latex spheres were attached to flagellar stubs on cells fixed to the surface of a glass slide. The angular speeds of the spheres were monitored in a weak optical trap by back-focal-plane interferometry in solutions containing different concentrations of the viscous agent Ficoll. Plots of relative torque (viscosity x speed) versus speed were obtained over a wide dynamic range (up to speeds of similar to 300 Hz) at three different temperatures, 22.7, 17.7, and 15.8 degrees C, Results obtained earlier by electrorotation (Berg and Turner, 1993, Biophys. J. 65:2201-2216) were confirmed. The motor operates in two dynamic regimes. At 23 degrees C, the torque is approximately constant up to a knee speed of nearly 200 Hz, and then it falls rapidly with speed to a zero-torque speed of similar to 350 Hz. In the low-speed regime, torque is insensitive to changes in temperature. In the high-speed regime, it decreases markedly at lower temperature. These results are consistent with models in which torque is generated by a powerstroke mechanism (Berry and Berg, 1999, Biophys. J, 76:580-587).