Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, Maryland 20892, USA.
Nature. 2010 May 27;465(7297):435-40. doi: 10.1038/nature09032. Epub 2010 Apr 28.
Dynamin is an atypical GTPase that catalyses membrane fission during clathrin-mediated endocytosis. The mechanisms of dynamin's basal and assembly-stimulated GTP hydrolysis are unknown, though both are indirectly influenced by the GTPase effector domain (GED). Here we present the 2.0 A resolution crystal structure of a human dynamin 1-derived minimal GTPase-GED fusion protein, which was dimeric in the presence of the transition state mimic GDP.AlF(4)(-).The structure reveals dynamin's catalytic machinery and explains how assembly-stimulated GTP hydrolysis is achieved through G domain dimerization. A sodium ion present in the active site suggests that dynamin uses a cation to compensate for the developing negative charge in the transition state in the absence of an arginine finger. Structural comparison to the rat dynamin G domain reveals key conformational changes that promote G domain dimerization and stimulated hydrolysis. The structure of the GTPase-GED fusion protein dimer provides insight into the mechanisms underlying dynamin-catalysed membrane fission.
动力蛋白是一种非典型的 GTP 酶，它在网格蛋白介导的胞吞作用中催化膜裂变。动力蛋白的基础和组装刺激的 GTP 水解机制尚不清楚，尽管两者都间接受到 GTP 酶效应结构域 (GED) 的影响。在这里，我们展示了一个来自人源动力蛋白 1 的最小 GTP 酶-GED 融合蛋白的 2.0 A 分辨率晶体结构，在过渡态类似物 GDP.AlF(4)(-) 的存在下，该结构呈二聚体形式。该结构揭示了动力蛋白的催化机制，并解释了如何通过 G 结构域二聚化来实现组装刺激的 GTP 水解。活性位点中存在的钠离子表明，在没有精氨酸手指的情况下，动力蛋白使用阳离子来补偿过渡态中产生的负电荷。与大鼠动力蛋白 G 结构域的结构比较揭示了促进 G 结构域二聚化和刺激水解的关键构象变化。GTP 酶-GED 融合蛋白二聚体的结构为动力蛋白催化的膜裂变机制提供了深入的了解。
