High-resolution cryo-EM maps show the nucleotide binding pocket of KIF1A in open and closed conformations
High-resolution cryo-EM maps show the nucleotide binding pocket of KIF1A in open and closed conformations
复制标题
DOI：
10.1038/sj.emboj.7601299
复制
发表时间：
2006-09-20
期刊：
影响因子：
11.4
通讯作者：
Hirokawa, Nobutaka
中科院分区：
文献类型：
--
作者：
Kikkawa, Masahide;Hirokawa, Nobutaka
驱动蛋白是一种由ATP驱动的微管（MT）马达，是细胞器运输的基础。虽然已经解决了许多驱动蛋白的晶体结构，结合的核苷酸和驱动蛋白的构象之间的耦合的结构证据是难以捉摸的。此外，由于MT在结构上的缺失，MT诱导的驱动蛋白ATP酶活性的结构基础尚不清楚。在这里，我们报告冷冻电子显微镜结构的单体驱动蛋白KIF 1A-MT复合物在两个核苷酸状态在约10埃的分辨率，足以揭示二级结构。这些高分辨率图谱显示了清晰的结构变化，表明从核苷酸到颈连接体的机械途径是通过马达核心旋转。此外，观察到新的核苷酸结合口袋构象不同于X射线晶体学结构;它在5 '-腺苷酰-亚氨二磷酸状态下是封闭的，但在ADP状态下是开放的。这些结果提示了单体驱动蛋白马达偏向扩散运动的结构模型。
Kinesin is an ATP-driven microtubule (MT)-based motor fundamental to organelle transport. Although a number of kinesin crystal structures have been solved, the structural evidence for coupling between the bound nucleotide and the conformation of kinesin is elusive. In addition, the structural basis of the MT-induced ATPase activity of kinesin is not clear because of the absence of the MT in the structure. Here, we report cryo-electron microscopy structures of the monomeric kinesin KIF1A-MT complex in two nucleotide states at about 10 angstrom resolution, sufficient to reveal the secondary structure. These high-resolution maps visualized clear structural changes that suggest a mechanical pathway from the nucleotide to the neck linker via the motor core rotation. In addition, new nucleotide binding pocket conformations are observed that are different from X-ray crystallographic structures; it is closed in the 5'-adenylyl-imidodiphosphate state, but open in the ADP state. These results suggest a structural model of biased diffusion movement of monomeric kinesin motor.