Thermodynamic aspects of ATP hydrolysis of actomyosin complex.
Thermodynamic aspects of ATP hydrolysis of actomyosin complex.
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肌动球蛋白复合物 ATP 水解的热力学方面
DOI：
10.1007/s41048-016-0032-5
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发表时间：
2016
影响因子：
--
通讯作者：
Feng W
中科院分区：
文献类型：
--
作者：
Zhang XC;Feng W
细胞成分的定向运动对所有真核细胞都是必不可少的，并且由主要由肌动蛋白-肌球蛋白细胞骨架蛋白复合物组成的机械酶系统驱动。这种复合物的结构和功能分析提供了重要的见解，强制执行和调节细胞内成分，如肌纤维，囊泡，以及细胞器的运动的机制。然而，所有肌球蛋白共同的ATP水解和力产生之间的能量耦合的结构基础仍然难以捉摸。在这里，我们简要回顾了广泛接受的概念，肌动蛋白-肌球蛋白循环的功能。然后，我们提出了一个模型的基础上的假设，即大部分的ATP中存储的化学能释放的ATP结合的步骤，而不是在水解步骤本身。重要的是，我们建议，这种能量是用来解离肌球蛋白从肌动蛋白丝，在肌动蛋白肌球蛋白功能循环的反应中最耗能的步骤。这表明解离步骤作为主要的能量储存，从而驱动肌动蛋白-肌球蛋白复合物的剩余功能循环。
Directional movement of cellular components is essential to all eukaryotic cells, and is driven by a mechanoenzymatic system consisting largely of the actin–myosin cytoskeletal protein complex. Structural and functional analysis of this complex has provided critical insights into the mechanisms that enforce and regulate the movement of intracellular components such as muscle fibers, vesicles, as well as organelles. However, the structural bases of energy coupling between ATP hydrolysis and force generation common for all myosins remain elusive. Here we briefly review the widely accepted concept of how the actin–myosin cycle functions. We then propose a model based on the assumption that most of the chemical energy stored in ATP is released in the step of ATP binding, not during the hydrolysis step per se. Importantly, we propose that this energy is used to dissociate myosin from the actin filament, the most energy-intensive step in the reaction of the actin–myosin functional cycle. This suggests that the dissociation step serves as the major energy storage, thus driving the remaining functional cycle of the actin–myosin complex.