Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD 20892, USA.
Cell. 2011 Sep 30;147(1):209-22. doi: 10.1016/j.cell.2011.09.003.
The GTPase dynamin catalyzes membrane fission by forming a collar around the necks of clathrin-coated pits, but the specific structural interactions and conformational changes that drive this process remain a mystery. We present the GMPPCP-bound structures of the truncated human dynamin 1 helical polymer at 12.2 Å and a fusion protein, GG, linking human dynamin 1's catalytic G domain to its GTPase effector domain (GED) at 2.2 Å. The structures reveal the position and connectivity of dynamin fragments in the assembled structure, showing that G domain dimers only form between tetramers in sequential rungs of the dynamin helix. Using chemical crosslinking, we demonstrate that dynamin tetramers are made of two dimers, in which the G domain of one molecule interacts in trans with the GED of another. Structural comparison of GG(GMPPCP) to the GG transition-state complex identifies a hydrolysis-dependent powerstroke that may play a role in membrane-remodeling events necessary for fission.
GTP 酶 dynamin 通过在网格蛋白包被凹陷的颈部周围形成一个环来催化膜裂变，但驱动这个过程的具体结构相互作用和构象变化仍然是一个谜。我们展示了结合 GMPPCP 的截断人源 dynamin 1 螺旋聚合物在 12.2Å 和一个融合蛋白 GG 的结构，GG 将人源 dynamin 1 的催化 G 结构域连接到其 GTP 酶效应结构域 (GED) 在 2.2Å。这些结构揭示了组装结构中 dynamin 片段的位置和连接性，表明 G 结构域二聚体仅在 dynamin 螺旋的连续梯级中的四聚体之间形成。通过使用化学交联，我们证明 dynamin 四聚体由两个二聚体组成，其中一个分子的 G 结构域与另一个分子的 GED 相互作用。GG(GMPPCP)与 GG 过渡态复合物的结构比较确定了一个依赖于水解的动力冲程，它可能在裂变所需的膜重塑事件中发挥作用。
