Faculty of Science and Engineering, Chuo University, Tokyo 112-8551, Japan.
Phys Rev Lett. 2010 May 14;104(19):198103. doi: 10.1103/PhysRevLett.104.198103.
Molecular motors drive mechanical motions utilizing the free energy liberated from chemical reactions such as ATP hydrolysis. Although it is essential to know the efficiency of this free energy transduction, it has been a challenge due to the system's microscopic scale. Here, we evaluate the single-molecule energetics of a rotary molecular motor, F1-ATPase, by applying a recently derived nonequilibrium equality together with an electrorotation method. We show that the sum of the heat flow through the probe's rotational degree of freedom and the work against an external load is almost equal to the free energy change per a single ATP hydrolysis under various conditions. This implies that F1-ATPase works at an efficiency of nearly 100% in a thermally fluctuating environment.
分子马达利用从化学反应（如 ATP 水解）中释放的自由能来驱动机械运动。尽管了解这种自由能传递的效率至关重要，但由于系统的微观尺度，这一直是一个挑战。在这里，我们通过应用最近推导的非平衡等式和电旋转方法来评估旋转分子马达 F1-ATP 酶的单分子能量学。我们表明，在各种条件下，探针旋转自由度的热流和对外加载的功之和几乎等于单个 ATP 水解的自由能变化。这意味着 F1-ATP 酶在热涨落环境中工作效率接近 100%。
