A myosin II mutation uncouples ATPase activity from motility and shortens step size
A myosin II mutation uncouples ATPase activity from motility and shortens step size
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DOI：
10.1038/35060110
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发表时间：
2001-03-01
影响因子：
21.3
通讯作者：
Spudich, JA
中科院分区：
文献类型：
--
作者：
Murphy, CT;Rock, RS;Spudich, JA
人们认为肌凝蛋白、运动蛋白和G蛋白的开关II在将核苷酸状态与蛋白质构象联系起来方面具有重要作用。在这里，我们研究了一个在开关II区域含有S456L替代的肌凝蛋白突变体。在这种蛋白质中，机械活性与ATP水解的化学能是分离的，因此它在肌动蛋白丝上的滑行速度只有野生型的十分之一。突变体在强结合状态下花费的时间更长，并且表现出更短的步长，这些都是体外速度降低的原因。这是第一个发现影响步长的肌凝蛋白单点突变。
It is thought that Switch II of myosin, kinesin and G proteins has an important function in relating nucleotide state to protein conformation, Here we examine a myosin mutant containing an S456L substitution in the Switch II region. In this protein, mechanical activity is uncoupled from the chemical energy of ATP hydrolysis so that its gliding velocity on actin filaments is only one-tenth of that of the wild type. The mutant spends longer in the strongly bound state and exhibits a shorter step size, which together account for the reduction in in vitro velocity. This is the first single point mutation in myosin that has been found to affect step size.