Cell 2011-09-30

A pseudoatomic model of the dynamin polymer identifies a hydrolysis-dependent powerstroke.

Joshua S Chappie, Jason A Mears, Shunming Fang, Marilyn Leonard, Sandra L Schmid, Ronald A Milligan, Jenny E Hinshaw, Fred Dyda

Index: Cell 147 , 209-222, (2011)

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Abstract

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.Copyright © 2011 Elsevier Inc. All rights reserved.