Mechanism of blebbistatin inhibition of myosin II
Mechanism of blebbistatin inhibition of myosin II
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DOI：
10.1074/jbc.m405319200
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发表时间：
2004-08-20
影响因子：
4.8
通讯作者：
Sellers, JR
中科院分区：
文献类型：
--
作者：
Kovács, M;Tóth, J;Sellers, JR
Blebbistatin是近年来发现的一种对肌球蛋白II具有高亲和力和选择性的小分子抑制剂。在这里，我们报告了其抑制机制的详细调查。Blebbistatin不与核苷酸竞争结合骨骼肌肌球蛋白亚片段-1。该抑制剂优先与ATP酶中间体结合，ADP和磷酸盐结合在活性位点，并减缓磷酸盐释放。Blebbistatin既不干扰肌球蛋白与肌动蛋白的结合，也不干扰ATP诱导的肌动球蛋白解离。相反，它阻止了低肌动蛋白亲和力的产物复合物中的肌球蛋白头。盲对接分子模拟表明，生产blebbistatin结合位点的肌球蛋白头是在水性腔之间的核苷酸口袋和肌动蛋白结合界面的裂缝。blebbistatin块肌球蛋白II在肌动蛋白分离状态的属性，使该化合物在肌肉生理学和探索细胞质肌球蛋白II亚型的细胞功能，而一个特定的肌球蛋白中间体的稳定赋予结构研究的巨大潜力。
Blebbistatin is a recently discovered small molecule inhibitor showing high affinity and selectivity toward myosin II. Here we report a detailed investigation of its mechanism of inhibition. Blebbistatin does not compete with nucleotide binding to the skeletal muscle myosin subfragment-1. The inhibitor preferentially binds to the ATPase intermediate with ADP and phosphate bound at the active site, and it slows down phosphate release. Blebbistatin interferes neither with binding of myosin to actin nor with ATP-induced actomyosin dissociation. Instead, it blocks the myosin heads in a products complex with low actin affinity. Blind docking molecular simulations indicate that the productive blebbistatin-binding site of the myosin head is within the aqueous cavity between the nucleotide pocket and the cleft of the actin-binding interface. The property that blebbistatin blocks myosin II in an actin-detached state makes the compound useful both in muscle physiology and in exploring the cellular function of cytoplasmic myosin II isoforms, whereas the stabilization of a specific myosin intermediate confers a great potential in structural studies.