title: Crystal structure of GTPase-activating domain from human MgcRacGAP.
abstract: Cytokinesis in animal cells relies on a centralspindlin complex consisting of male germ cell RacGap (MgcRacGAP) and mitotic kinesin-like protein 1 (MKLP1). Rho GTPases act as molecular switches to regulate the actin cytoskeleton for cytokinesis, of which Rac1 is regulated by MgcRacGAP. In this study, we determined the crystal structure of the GTPase-activating protein (GAP) domain of MgcRacGAP at a resolution of 1.9Å. The conformation of Arg385, which is a key residue for GAP activity, was found to be different from that of previously reported GAP proteins, and MgcRacGAP (residues 348-546) was found to exist as a monomer in solution, according to Stokes radii. We also measured the GAP activity of MgcRacGAP mutants for Rac1.
authors.affiliation: Department of Bio & Nano Chemistry, Kookmin University, Seoul 136-702, Republic of Korea.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Matsuura
authors.forename: Hyung Ho
authors.initials: HH
authors.lastname: Lee
mesh_terms: D019943:Amino Acid Substitution / Q000235:genetics; D018360:Crystallography, X-Ray; D048749:Cytokinesis / Q000235:genetics; D004789:Enzyme Activation / Q000235:genetics; D020690:GTPase-Activating Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D006801:Humans; D008297:Male; D046912:Multiprotein Complexes / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D016297:Mutagenesis, Site-Directed; D010446:Peptide Fragments / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011487:Protein Conformation; D017434:Protein Structure, Tertiary / Q000235:genetics; D020830:rac1 GTP-Binding Protein / Q000235:genetics / Q000378:metabolism
chemical_list: D020690:GTPase-Activating Proteins; D046912:Multiprotein Complexes; D010446:Peptide Fragments; C107953:RAC1 protein, human; C115995:mgcRacGAP; D020830:rac1 GTP-Binding Protein