Chemical peristalsis.
Chemical peristalsis.
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DOI：
10.1073/pnas.0409341102
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发表时间：
2005-02
影响因子：
11.1
通讯作者：
R. Astumian
中科院分区：
文献类型：
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作者：
R. Astumian
部分模仿蛋白质马达非凡能力的分子最近被化学合成。一种很有前途的方法是基于物理互锁的大分子复合物，如轮烷和链烷。利用后者，Leigh等人[Leigh， D. A., Wong， J. K. Y., Dehez， F. & Zerbetto， F. (2003) Nature 424, 174-179]构建了一个分子转子，其中两个小环被光脉冲诱导，在第三个更大的环周围单向移动。其原理类似于蠕动泵的工作原理。然而，与宏观蠕动不同的是，在宏观蠕动中，行波迫使物质通过一系列单向阀，化学蠕动机制并不直接导致小环移动，而只是改变了能量学，运动本身是由能量障碍上的热激活引起的。由这种机构运转的发动机是“布朗”发动机。在这里，我们描述了一个最小的双态机制的链式分子马达。虽然平衡过程引起的波动不能驱动定向运动，但非平衡波动，无论是外部产生的还是由远离平衡的化学反应产生的，甚至可以在外部扭矩的作用下驱动旋转。我们讨论了电机和环境之间信息和能量输入和输出的可能架构，并给出了最大热力学效率的简单表达式。提出的布朗运动机制与Yasuda等人观察到的高效率一致[Yasuda， Y., Noji， H., Kinoshita， K. & Yoshida， M. (1998) Cell 93, 1117-1124]， F(1)-ATP合成酶作为atp驱动的分子转子运行。
Molecules that emulate in part the remarkable capabilities of protein motors were recently chemically synthesized. A promising approach is based on physically interlocked macromolecular complexes such as rotaxanes and catenanes. Using the latter, Leigh et al. [Leigh, D. A., Wong, J. K. Y., Dehez, F. & Zerbetto, F. (2003) Nature 424, 174-179] constructed a molecular rotor in which two small rings are induced by pulses of light to move unidirectionally around a third, larger ring. The mechanism is similar to that by which a peristaltic pump operates. Unlike macroscopic peristalsis, however, in which a traveling wave forces material through a series of one-way valves, the chemical peristaltic mechanism does not directly cause the small rings to move but only alters the energetics, with the motion itself arising by thermal activation over energy barriers. Engines operating by this mechanism are "Brownian" motors. Here we describe a minimal two-state mechanism for a catenane-based molecular motor. Although fluctuations caused by equilibrium processes cannot drive directed motion, nonequilibrium fluctuations, whether generated externally or by a far-from-equilibrium chemical reaction, can drive rotation even against an external torque. We discuss a possible architecture for input and output of information and energy between the motor and its environment and give a simple expression for the maximum thermodynamic efficiency. The proposed Brownian motor mechanism is consistent with the high efficiency observed by Yasuda et al. [Yasuda, Y., Noji, H., Kinoshita, K. & Yoshida, M. (1998) Cell 93, 1117-1124] for the F(1)-ATP synthase operating as an ATP-powered molecular rotor.