Energy transduction in myosin
Energy transduction in myosin
复制标题
肌球蛋白的能量转导
DOI：
10.1016/0968-0004(84)90303-7
复制
发表时间：
1984
影响因子：
13.8
通讯作者：
J. Shriver
中科院分区：
文献类型：
--
作者：
J. Shriver
现在普遍认为，肌肉收缩所需的力是肌球蛋白横桥结构转变的结果。最近的光谱研究表明，肌球蛋白可以存在于两种不同的结构状态。这两种状态之间的平衡是以这样一种方式保持的，即它可以在实验条件的微小变化下被强制向任何一个方向移动。在A TP水解过程中，肌球蛋白被迫在两种状态之间振荡，伴随着自由能耗散。ATP水解的化学能被转换成肌球蛋白结构在两种状态之间的机械转换。肌球蛋白A Tactinase活性位点可被视为负责转换的时间依赖性效应位点。这两种状态之间的平衡变化已经被证明是与肌肉纤维中张力的变化平行的。这两种肌球蛋白状态可能与肌肉中产生力量的动力冲程直接相关。矢量过程与化学（或光化学）反应的酶促偶联通常被称为能量转导。例子包括在呼吸链中一系列氧化还原反应导致的H+穿过脂质双层的泵送，或者由于促旋酶的ATP水解导致的超螺旋引入环状DNA。能量转换是所有相关反应（正向和反向）的性质，不能被认为是一个单步过程。然而，在转导周期中酶中发生的一些事件与矢量过程直接相关，例如离子穿过膜的实际运动，或在转导周期中肌球蛋白跨桥的动力冲程。
It is now generally believed that the force necessary for muscle contraction results from a structural transition in the myosin crossbridge. Recent spectroscopic studies have indicated that myosin can exist in two distinct structural states. The equilibrium between the two states is poised in such a way that it can be forced in either direction with minor changes in experimental conditions. During A TP hydrolysis, myosin is forced to oscillate between the two states concomitantly with free energy dissipation. The chemical energy of A TP hydrolysis is transduced into a mechanical switching of the myosin structure between the two states. The myosin A TPase active site may be viewed as a time-dependent effector site responsible for the switching. Changes in the equilibrium between the two states have been shown to parallel changes in tension in muscle fibers. It is possible that the two myosin states may be directly correlated to the force-producing power stroke in muscle, The enzymatic coupling of vectorial processes to chemical (or photochemical) reactions is often referred to as energy transduction. Examples include pumping of H+ across a lipid bilayer as a result of a series of oxidation-reduction reactions in the respiratory chain, or the introduction of superhelices into circular DNA as a result of ATP hydrolysis by a gyrase. Energy transduction is a property of all the reactions involved (both forward and reverse) and cannot be considered a single-step process 1. However, there are events which occur in the enzyme during transduction cycles which are directly associated with the vectorial process, eg the actual movement of an ion across a membrane, or the power stroke of the myosin crossbridge during
腺苷 5-二磷酸和腺苷 5-（β，γ-亚胺三磷酸）与亚片段 1 和 acto 亚片段 1 结合的瞬时动力学。
影响因子：
2.9
作者：
Trybus,KM;Taylor,EW
通讯作者：
Taylor,EW