Cooperation between multiple heads in moving dynein molecule

胞浆动力蛋白是一种双头微管运动蛋白。虽然动蛋白是通过手部机制移动的，但动力蛋白的行走机制尚不清楚。由于动力蛋白的运动域比步长大得多，所以动力蛋白的两个头部被认为使用了MT的多个原丝。在这里，我们报告了动力蛋白和动蛋白在锌诱导的微管蛋白聚合物(锌片)上的运动，其中只有一个原丝可以被马达蛋白使用。动力蛋白和动蛋白在锌板上以与MTS相似的速度单向运动，表明动力蛋白和动蛋白都可以在单个原丝上行走，多排平行的原丝对运动不是必需的。这些发现为动力蛋白如何利用这两个巨大的运动域进行分子行走提供了线索。

Cytoplasmic dynein is a two-headed microtubule (MT) motor protein. While kinesin moves by a hand-over-hand mechanism, the dynein walking mechanism is unknown. As the dynein motor domain is much larger than the step size, the two heads of dynein are thought to use multiple protofilaments of MT. Here we report dynein and kinesin motility on zinc-induced tubulin polymer (zinc-sheet), where only one protofilament can be used by motor proteins. Dynein and kinesin moved unidirectionally on a zinc-sheet at a similar velocity as MTs, demonstrating that both dynein and kinesin can walk on a single protofilament and multiple rows of parallel protofilaments are not essential for motility. These findings provide a clue as to how dynein uses the two huge motor domains for molecular walking.