Harrison B C, Marchese-Ragona S P, Gilbert S P, Cheng N, Steven A C, Johnson K A
Department of Molecular and Cell Biology, Pennsylvania State University, University Park, 16802.
Nature. 1993 Mar 4;362(6415):73-5. doi: 10.1038/362073a0.
Kinesin, a microtubule-dependent ATPase, is believed to be involved in anterograde axonal transport. The kinesin head, which contains both microtubule and ATP binding sites, has the necessary components for the generation of force and motility. We have used saturation binding and electron microscopy to examine the interaction of the kinesin motor domain with the microtubule surface and found that binding saturated at one kinesin head per tubulin heterodimer. Both negative staining and cryo-electron microscopy revealed a regular pattern of kinesin bound to the microtubule surface, with an axial repeat of 8 nm. Optical diffraction analysis of decorated microtubules showed a strong layer-line at this spacing, confirming that one kinesin head binds per tubulin heterodimer. The addition of Mg-ATP to the microtubule-kinesin complex resulted in the complete dissociation of kinesin from the microtubule surface.
驱动蛋白是一种依赖微管的ATP酶，被认为参与轴突的顺向运输。驱动蛋白头部含有微管和ATP结合位点，具备产生力和运动性的必要组件。我们利用饱和结合和电子显微镜技术研究了驱动蛋白运动结构域与微管表面的相互作用，发现每个微管蛋白异二聚体结合一个驱动蛋白头部时结合达到饱和。负染色和冷冻电子显微镜观察均显示，驱动蛋白在微管表面呈规则排列，轴向重复距离为8纳米。对被修饰微管的光学衍射分析表明，在此间距处有一条很强的层线，证实每个微管蛋白异二聚体结合一个驱动蛋白头部。向微管-驱动蛋白复合物中添加Mg-ATP会导致驱动蛋白从微管表面完全解离。
