Overlapping hand-over-hand mechanism of single molecular motility of cytoplasmic dynein
Overlapping hand-over-hand mechanism of single molecular motility of cytoplasmic dynein
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DOI：
10.1073/pnas.0508511103
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发表时间：
2006-04-11
影响因子：
11.1
通讯作者：
Higuchi, H
中科院分区：
文献类型：
--
作者：
Toba, S;Watanabe, TM;Higuchi, H
动力蛋白和驱动蛋白之间的结构差异表明动力蛋白运动的独特分子机制。测量单个动力蛋白分子的机械特性对于揭示其运动机制至关重要。我们测量的步长和力的活性细胞质动力蛋白的单分子通过使用光学陷阱和荧光成像具有高的时间分辨率。动力蛋白的运动速度为800 nm/s，与细胞中报道的一致。最大作用力为7-8 pN，与ATP浓度无关，与驱动蛋白相似。动力蛋白表现出向前和偶尔向后的步骤约为8 nm，独立于负载。建议大动力蛋白头通过使用重叠的双手交替机构来采取16-nm的步骤。
Structural differences between dynein and kinesin suggest a unique molecular mechanism of dynein motility. Measuring the mechanical properties of a single molecule of dynein is crucial for revealing the mechanisms underlying its movement. We measured the step size and force produced by single molecules of active cytoplasmic dynein by using an optical trap and fluorescence imaging with a high temporal resolution. The velocity of dynein movement, 800 nm/s, is consistent with that reported in cells. The maximum force of 7-8 pN was independent of the ATP concentration and similar to that of kinesin. Dynein exhibited forward and occasional backwards steps of approximate to 8 nm, independent of load. it is suggested that the large dynein heads take 16-nm steps by using an overlapping hand-over-hand mechanism.