2IF0

Crystal Structure of mouse Rab27b bound to GDP in monoclinic space group

Summary for 2IF0

• Entry DOI: 10.2210/pdb2if0/pdb
• Related: 2IEY 2IEZ
• Descriptor: Ras-related protein Rab-27B, MAGNESIUM ION, GUANOSINE-5'-DIPHOSPHATE, ... (4 entities in total)
• Functional Keywords: rab27, gtpase, rab, signaling protein, gdp, swapping
• Biological source: Mus musculus (house mouse)
• Cellular location: Membrane; Lipid-anchor (By similarity): Q99P58
• Total number of polymer chains: 2
• Total formula weight: 46386.41

Authors

Chavas, L.M.G.,Torii, S.,Kamikubo, H.,Kawasaki, M.,Ihara, K.,Kato, R.,Kataoka, M.,Izumi, T.,Wakatsuki, S. (deposition date: 2006-09-19, release date: 2007-05-01, Last modification date: 2024-10-30)

Primary citation

Chavas, L.M.G.,Torii, S.,Kamikubo, H.,Kawasaki, M.,Ihara, K.,Kato, R.,Kataoka, M.,Izumi, T.,Wakatsuki, S.
Structure of the small GTPase Rab27b shows an unexpected swapped dimer
Acta Crystallogr.,Sect.D, 63:769-779, 2007

PubMed Abstract: Members of the Rab family of small GTPases regulate membrane traffic within the cell by recruiting their specific effectors in a nucleotide-dependent manner. The Rab27 subfamily consists of Rab27a and Rab27b, which share 70% sequence identity. By interacting with a large set of effector proteins such as melanophilin and granuphilin, both Rab27a and Rab27b regulate the exocytosis of secretory lysosomes. Here, the crystal structures of mouse Rab27b in complex with GDP have been determined in three distinct crystal lattices. Surprisingly, Rab27b-GDP exists in an open conformation with protruding switch and interswitch regions, which are stabilized through dimerization by means of domain-swapping in the crystals. In contrast, small-angle X-ray scattering measurements showed an extended monomer form of Rab27b in solution. The observed dimer formation of Rab27b-GDP in the crystals would restrain the highly flexible switch regions. Possible biological implications of this atypical structure of Rab27b and its plausible influence in effector interaction are discussed.

PubMed: 17582168
DOI: 10.1107/S0907444907019725

Experimental method

X-RAY DIFFRACTION (2.8 Å)