Khan S, Meister M, Berg H C
J Mol Biol. 1985 Aug 20;184(4):645-56. doi: 10.1016/0022-2836(85)90310-9.
The motion of tethered cells of Streptococcus was analyzed at low values of protonmotive force (delta p). Cells repeatedly energized and de-energized stopped at discrete angular positions, indicating a rotational symmetry of barriers to rotation of order 5 or 6. At values of delta p smaller than -30 mV, constraints imposed by these barriers were evident when cells were starved and gradually energized, but not when they were energized first and then gradually de-energized. At values of delta p larger than about -30 mV, the cells behaved as if there were no barriers. Cells spinning in this regime also executed rotational Brownian movement. At energy levels above threshold, the motor determines torque; it does not fix the position of the rotor relative to the stator.
在低质子动力（Δp）值下分析了链球菌系留细胞的运动。反复进行能量供应和去能的细胞会在离散的角位置停止，这表明存在5或6阶旋转障碍的旋转对称性。在Δp小于 -30 mV的值时，当细胞饥饿并逐渐供能时，这些障碍施加的限制很明显，但当它们先供能然后逐渐去能时则不明显。在Δp大于约 -30 mV的值时，细胞的行为就好像没有障碍一样。在这种状态下旋转的细胞也会进行旋转布朗运动。在高于阈值的能量水平下，马达决定扭矩；它并不固定转子相对于定子的位置。
