Vale R D, Soll D R, Gibbons I R
Department of Pharmacology, University of California School of Medicine, San Francisco 94143.
Cell. 1989 Dec 1;59(5):915-25. doi: 10.1016/0092-8674(89)90614-4.
Dynein is a multisubunit ATPase that powers microtubule-based motility. We find that a dissociated dynein particle containing the beta heavy chain subunit translocates microtubules unidirectionally over a glass surface in the presence of ATP. However, after nucleotide hydrolysis is inhibited by vanadate, unidirectional translocation ceases, and microtubules instead undergo irregular back-and-forth motion along their longitudinal axes. Quantitative analysis reveals that this motion is due to thermal-driven diffusion, but, unlike a particle undergoing Brownian motion, the diffusion is restricted to one dimension. The properties of the diffusional movement indicate that dynein can interact with microtubules in a way that permits the latter to diffuse only along their longitudinal axes. This weak binding interaction may constitute an important intermediate state in dynein's force-generating cycle.
动力蛋白是一种多亚基ATP酶，为基于微管的运动提供动力。我们发现，在ATP存在的情况下，含有β重链亚基的解离动力蛋白颗粒在玻璃表面上单向移动微管。然而，当钒酸盐抑制核苷酸水解后，单向移动停止，微管反而沿其纵轴进行不规则的来回运动。定量分析表明，这种运动是由热驱动扩散引起的，但与经历布朗运动的粒子不同，扩散仅限于一维。扩散运动的特性表明，动力蛋白可以与微管以一种允许微管仅沿其纵轴扩散的方式相互作用。这种弱结合相互作用可能构成动力蛋白产生力的循环中的一个重要中间状态。
