Myosin V is a left-handed spiral motor on the right-handed actin helix
Myosin V is a left-handed spiral motor on the right-handed actin helix
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DOI：
10.1038/nsb803
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发表时间：
2002-06-01
期刊：
影响因子：
--
通讯作者：
Ishiwata, S
中科院分区：
文献类型：
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作者：
Ali, MY;Uemura, S;Ishiwata, S
肌球蛋白V是一个双头的、以肌动蛋白为基础的分子马达，与细胞器运输有关。以前，单个肌球蛋白V分子已经被证明沿着肌动蛋白细丝以类似于36纳米的离散步长进行连续移动。然而，36 nm是肌动蛋白的螺旋重复长度，之前实验的几何形状可能迫使头部与肌动蛋白一侧相隔36 nm的位置结合或停止。为了观察不受约束的运动，我们在溶液中悬浮了一根肌动蛋白细丝，并连接了一个携带珠子的肌球蛋白V分子。这个双链以左手螺旋的形式绕着丝状体移动，而不考虑右手的肌动蛋白螺旋。我们的结果表明，肌球蛋白V是一种步进式行走机制，在这种机制中，肌球蛋白V定位和定位未结合的头部，使头部落在肌动蛋白双螺旋相反链上的第11或13个肌动蛋白亚基。
Myosin V is a two-headed, actin-based molecular motor implicated in organelle transport. Previously, a single myosin V molecule has been shown to move processively along an actin filament in discrete similar to36 nm steps. However, 36 nm is the helical repeat length of actin, and the geometry of the previous experiments may have forced the heads to bind to, or halt at, sites on one side of actin that are separated by 36 nm. To observe unconstrained motion, we suspended an actin filament in solution and attached a single myosin V molecule carrying a bead duplex. The duplex moved as a left-handed spiral around the filament, disregarding the right-handed actin helix. Our results indicate a stepwise walking mechanism in which myosin V positions and orients the unbound head such that the head will land at the 11th or 13th actin subunit on the opposing strand of the actin double helix.