title: Refinement of the structure of human Rab5a GTPase domain at 1.05 A resolution.
abstract: Rab5 is a GTPase that regulates early endosome fusion. Its GTPase domain crystal structure is reported here at 1.05 A resolution in complex with a GTP-analog molecule. It provides the highest resolution three-dimensional model so far obtained for proteins from the Ras-like GTPase family. This study allows extension of structural examination of the GTPase machinery as well as of high-resolution protein structures in general. For example, a buried water-molecule network was observed underneath the switch regions, which is consistent with the functional roles of these regions in the molecular-switching process. Furthermore, residues of multiple conformation and clustered distribution of anisotropic thermal motions of the protein molecule may have general implications for the function of Ras-like GTPases.
authors.affiliation: Crystallography Research Program of Oklahoma Medical Research Foundation, 825 NE 13th Street, Oklahoma City, OK 73104, USA. terzyans@omrf.ouhsc.edu
authors.forename: Simon
authors.initials: S
authors.lastname: Terzyan
authors.forename: Guangyu
authors.initials: G
authors.lastname: Zhu
authors.forename: Guangpu
authors.initials: G
authors.lastname: Li
authors.forename: Xuejun C
authors.initials: XC
authors.lastname: Zhang
mesh_terms: D016880:Anisotropy; D018360:Crystallography, X-Ray / Q000379:methods*; D004926:Escherichia coli / Q000235:genetics; D006151:Guanosine / Q000031:analogs & derivatives / Q000378:metabolism; D006801:Humans; D006860:Hydrogen Bonding; D008958:Models, Molecular; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics; D020696:rab5 GTP-Binding Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
chemical_list: D011994:Recombinant Proteins; D006151:Guanosine; D020696:rab5 GTP-Binding Proteins