Conibear P B, Geeves M A
Department of Biochemistry, University of Leicester, Leicester LE1 7RH, United Kingdom.
Biophys J. 1998 Aug;75(2):926-37. doi: 10.1016/S0006-3495(98)77581-2.
An extensive series of experiments in this laboratory has shown that the binding of actin to rabbit skeletal muscle myosin subfragment-1 (a single-headed subfragment) can be described by a two-step model, with formation of a weakly bound complex, the A-state, followed by an isomerization to a more tightly bound complex, the R-state. In this paper, we report on additional experiments comparing the subfragment-1 with heavy meromyosin (a two-headed subfragment). Using a modeling approach, we have quantitated the two-step binding for each of the two heads. This indicates that the binding is cooperative and leads to a more complex view of the acto-myosin interaction than has previously been acknowledged. Implications for the dynamic behavior of the two heads during muscle contraction are discussed.
本实验室进行的一系列广泛实验表明，肌动蛋白与兔骨骼肌肌球蛋白亚片段-1（单头亚片段）的结合可用两步模型来描述，即先形成弱结合复合物（A态），随后异构化为结合更紧密的复合物（R态）。在本文中，我们报告了将亚片段-1与重酶解肌球蛋白（双头亚片段）进行比较的额外实验。我们采用建模方法，对两个头部各自的两步结合进行了定量。这表明这种结合具有协同性，并且对肌动蛋白-肌球蛋白相互作用的认识比以往所承认的更为复杂。文中还讨论了这对肌肉收缩过程中两个头部动态行为的影响。
