Universal optimal working cycles of molecular motors
Universal optimal working cycles of molecular motors
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DOI：
10.1039/c0cp02118k
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发表时间：
2011-01-01
影响因子：
3.3
通讯作者：
Wang, Zhisong
中科院分区：
文献类型：
--
作者：
Efremov, Artem;Wang, Zhisong
能够定向轨迹行走或旋转的分子马达在活细胞中大量存在，并激发了人工纳米马达的新兴领域。一些生物马达可以将化学燃料中90%的自由能量转化为可用的机械功，而同样的马达仍然保持着足以满足细胞功能的速度。这项研究揭示了一种新的普遍优化制度，它相当于分子马达的热力学最佳工作制度，但在宏观引擎中是不熟悉的。在零能量耗散的理想情况下，分子马达的普遍优化工作周期是无限慢的，就像热机的卡诺循环一样。但当少量的能量耗散使能效从100%线性下降时，根据玻尔兹曼定律，速度将呈指数级恢复。一种主要生物因子(激动素)的实验数据表明，活细胞在很大程度上已经接近了普遍的优化机制，这支持了生物因子的极高效率和速度之间的权衡。普遍的最优化及其实用的可达性是分子系统在促进马达功能方面相对于宏观引擎的独特热力学优势。这些发现对生物动植物的自然进化以及人工动植物的发展具有重要的意义。
Molecular motors capable of directional track-walking or rotation are abundant in living cells, and inspire the emerging field of artificial nanomotors. Some biomotors can convert 90% of free energy from chemical fuels into usable mechanical work, and the same motors still maintain a speed sufficient for cellular functions. This study exposed a new regime of universal optimization that amounts to a thermodynamically best working regime for molecular motors but is unfamiliar in macroscopic engines. For the ideal case of zero energy dissipation, the universally optimized working cycle for molecular motors is infinitely slow like Carnot cycle for heat engines. But when a small amount of energy dissipation reduces energy efficiency linearly from 100%, the speed is recovered exponentially due to Boltzmann's law. Experimental data on a major biomotor (kinesin) suggest that the regime of universal optimization has been largely approached in living cells, underpinning the extreme efficiency-speed trade-off in biomotors. The universal optimization and its practical approachability are unique thermodynamic advantages of molecular systems over macroscopic engines in facilitating motor functions. The findings have important implications for the natural evolution of biomotors as well as the development of artificial counterparts.