Subtilisin cleavage of actin inhibits in vitro sliding movement of actin filaments over myosin.
Subtilisin cleavage of actin inhibits in vitro sliding movement of actin filaments over myosin.
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DOI：
10.1083/jcb.111.2.465
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发表时间：
1990-08
期刊：
影响因子：
--
通讯作者：
Reisler E
中科院分区：
文献类型：
--
作者：
Schwyter DH;Kron SJ;Toyoshima YY;Spudich JA;Reisler E
被枯草杆菌酶切割的肌动蛋白保留了完整肌动蛋白的一些性质，包括结合重肌球蛋白(HMM)、被ATP解离HMM以及激活HMM ATPase活性。切割和完整肌动蛋白的acto-HMM ATPase的Vmax相似，Km值不同。完整肌动蛋白共聚物和裂解肌动蛋白共聚物刺激HMM的ATPase活性与共聚物中完整肌动蛋白的含量呈线性关系。完整的和切割的肌动蛋白之间最重要的区别是在体外运动测试中观察到肌动蛋白在HMM涂层表面上的滑动运动。在本实验中，只有30%的被切割的肌动蛋白细丝出现移动，而且移动的细丝的速度大约是完整肌动蛋白细丝的30%。这些结果表明，肌动蛋白细丝的运动可以从肌球蛋白ATPase活性的激活中解脱出来，并依赖于肌动蛋白结构的完整性，可能还依赖于肌动蛋白分子的动态变化。
Subtilisin cleaved actin was shown to retain several properties of intact actin including the binding of heavy meromyosin (HMM), the dissociation from HMM by ATP, and the activation of HMM ATPase activity. Similar Vmax but different Km values were obtained for acto- HMM ATPase with the cleaved and intact actins. The ATPase activity of HMM stimulated by copolymers of intact and cleaved actin showed a linear dependence on the fraction of intact actin in the copolymer. The most important difference between the intact and cleaved actin was observed in an in vitro motility assay for actin sliding movement over an HMM coated surface. Only 30% of the cleaved actin filaments appeared mobile in this assay and moreover, the velocity of the mobile filaments was approximately 30% that of intact actin filaments. These results suggest that the motility of actin filaments can be uncoupled from the activation of myosin ATPase activity and is dependent on the structural integrity of actin and perhaps, dynamic changes in the actin molecule.