title: The dynamin A ring complex: molecular organization and nucleotide-dependent conformational changes.
abstract: Here we show that Dictyostelium discoideum dynamin A is a fast GTPase, binds to negatively charged lipids, and self-assembles into rings and helices in a nucleotide-dependent manner, similar to human dynamin-1. Chemical modification of two cysteine residues, positioned in the middle domain and GTPase effector domain (GED), leads to altered assembly properties and the stabilization of a highly regular ring complex. Single particle analysis of this dynamin A* ring complex led to a three-dimensional map, which shows that the nucleotide-free complex consists of two layers with 11-fold symmetry. Our results reveal the molecular organization of the complex and indicate the importance of the middle domain and GED for the assembly of dynamin family proteins. Nucleotide-dependent changes observed with the unmodified and modified protein support a mechanochemical action of dynamin, in which tightening and stretching of a helix contribute to membrane fission.
authors.affiliation: Department of Biophysics, Max-Planck-Institute for Medical Research, Jahnstrasse 29, D-69120 Heidelberg, Germany.
authors.forename: Boris
authors.initials: B
authors.lastname: Klockow
authors.forename: Willem
authors.initials: W
authors.lastname: Tichelaar
authors.forename: Dean R
authors.initials: DR
authors.lastname: Madden
authors.forename: Hartmut H
authors.initials: HH
authors.lastname: Niemann
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Akiba
authors.forename: Keiko
authors.initials: K
authors.lastname: Hirose
authors.forename: Dietmar J
authors.initials: DJ
authors.lastname: Manstein
mesh_terms: D000818:Animals; D004023:Dictyostelium / Q000378:metabolism*; D019281:Dimerization; D034281:Dynamins; D020558:GTP Phosphohydrolases / Q000737:chemistry / Q000378:metabolism / Q000648:ultrastructure; D006801:Humans; D011487:Protein Conformation; D015800:Protozoan Proteins / Q000737:chemistry / Q000378:metabolism / Q000648:ultrastructure
chemical_list: D015800:Protozoan Proteins; D020558:GTP Phosphohydrolases; D034281:Dynamins; C117420:dynamin A protein, Dictyostelium discoideum