Cooperation between multiple heads in moving dynein molecule

细胞质动力蛋白是一种双头微管（MT）马达蛋白。虽然驱动蛋白的移动通过一个手在手的机制，动力蛋白步行机制是未知的。由于动力蛋白的运动域远大于步长，因此动力蛋白的两个头部被认为使用MT的多个原丝。在这里，我们报告动力蛋白和驱动蛋白运动的锌诱导的微管蛋白聚合物（锌片），只有一个原丝可以使用的马达蛋白。动力蛋白和驱动蛋白在锌片上以与MT相似的速度单向移动，表明动力蛋白和驱动蛋白都可以在单个原丝上行走，并且多排平行的原丝对于运动性不是必需的。这些发现为动力蛋白如何利用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.