PATHWAY OF PROCESSIVE ATP HYDROLYSIS BY KINESIN
PATHWAY OF PROCESSIVE ATP HYDROLYSIS BY KINESIN
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DOI：
10.1038/373671a0
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发表时间：
1995-02-23
期刊：
影响因子：
64.8
通讯作者：
JOHNSON, KA
中科院分区：
文献类型：
--
作者：
GILBERT, SP;WEBB, MR;JOHNSON, KA
直接测量运动蛋白从微管解离、运动蛋白释放磷酸盐和ADP以及运动蛋白与微管重新结合的动力学已经确定了运动蛋白ATPase循环的机制。在低盐浓度下，ATP水解的加工率为每个位点10个分子，但在较高盐浓度时，则降低到每个位点一个ATP。肌动蛋白在三磷酸腺苷水解后从微管中解离。这一步是限速的。随后Kinesin ADP与微管的重新结合速度很快，因此Kinesin在解离状态下只花了其占空比的一小部分。这些结果为骨骼肌球蛋白和肌动蛋白之间的运动性差异提供了解释。
Direct measurement of the kinetics of kinesin dissociation from microtubules, the release of phosphate and ADP from kinesin, and rebinding of kinesin to the microtubule have defined the mechanism for the kinesin ATPase cycle. The processivity of ATP hydrolysis is ten molecules per site at low salt concentration but is reduced to one ATP per site at higher salt concentration. Kinesin dissociates from the microtubule after ATP hydrolysis. This step is rate-limiting. The subsequent rebinding of kinesin ADP to the microtubule is fast, so kinesin spends only a small fraction of its duty cycle in the dissociated state. These results provide an explanation for the motility differences between skeletal myosin and kinesin.