Cooperative rigor binding of myosin to actin is a function of F-actin structure
Cooperative rigor binding of myosin to actin is a function of F-actin structure
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DOI：
10.1006/jmbi.1996.0761
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发表时间：
1997-02-07
影响因子：
5.6
通讯作者：
Egelman, EH
中科院分区：
文献类型：
--
作者：
Orlova, A;Egelman, EH
现在已经描述了纯F-肌动蛋白丝内合作行为的许多方面。我们使用了两个肌球蛋白片段，重肌球蛋白（HMM）和亚片段1（S1），来观察与不同形式的F-肌动蛋白的严格结合。Ca 2+结合在肌动蛋白的高亲和力金属结合位点上，HMM的结合具有很大的协同性，而S1没有协同性。与Mg 2+结合在高亲和力bo网站，或与稳定的肌动蛋白的亚结构域-2的构象的条件下，有没有看到与HMM或S1的协同性。这些结果表明，HMM的两个头部可以诱导F-actin的结构变化，而S1的单个头部则没有观察到这种变化。他们还支持的概念，即肌球蛋白的F-肌动蛋白的结合诱导肌动蛋白的亚结构域-2的构象变化，在某些条件下，这种构象变化可以通过肌动蛋白丝协同传播。(C)出版社：Academic Press Limited。
Many aspects of cooperative behavior within pure F-actin filaments have now been described. We have used two myosin fragments, heavy meromyosin (HMM) and Subfragment 1 (S1), to look at the rigor binding to different forms of F-actin. With Ca2+ bound at the high-affinity metal binding site in actin, there is a very large cooperativity in the binding of HMM, but no cooperativity for S1. With Mg2+ bound at the high affinity bo site, or with conditions that stabilize the conformation of subdomain-2 of actin, there is no cooperativity seen with either HMM or S1. These results show that the two heads of HMM can induce structural changes in F-actin that are not observed with the single head of S1. They also support the notion that the binding of myosin to F-actin induces a conformational change in subdomain-2 of actin, and that under certain conditions this conformational change can be cooperatively propagated through an actin filament. (C) 1997 Academic Press Limited.