title: Large nucleotide-dependent conformational change in Rab28.
abstract: Rab GTPases are essential regulators of membrane trafficking. We report crystal structures of Rab28 in the active (GppNHp-bound) and inactive (GDP-3'P-bound) forms at 1.5 and 1.1A resolution. Rab28 is a distant member of the Rab family. While the overall fold of Rab28 resembles that of other Rab GTPases, it undergoes a larger nucleotide-dependent conformational change than other members of this family. Added flexibility resulting from a double-glycine motif at the beginning of switch 2 might partially account for this observation. The double-glycine motif, which is conserved in the Arf family, only occurs in Rab28 and Rab7B of the Rab family, and may have a profound effect on their catalytic activities.
authors.affiliation: Department of Physiology, University of Pennsylvania School of Medicine, 3700 Hamilton Walk, A507 Richards Building, Philadelphia, PA 19104-6085, USA.
authors.forename: Sung Haeng
authors.initials: SH
authors.lastname: Lee
authors.forename: Kyuwon
authors.initials: K
authors.lastname: Baek
authors.forename: Roberto
authors.initials: R
authors.lastname: Dominguez
mesh_terms: D000595:Amino Acid Sequence; D018360:Crystallography, X-Ray; D006153:Guanosine Diphosphate / Q000737:chemistry*; D006165:Guanylyl Imidodiphosphate / Q000737:chemistry*; D006801:Humans; D011487:Protein Conformation; D020691:rab GTP-Binding Proteins / Q000737:chemistry*
chemical_list: D006153:Guanosine Diphosphate; D006165:Guanylyl Imidodiphosphate; C503250:RAB28 protein, human; D020691:rab GTP-Binding Proteins