1tu4

From Proteopedia

Revision as of 14:58, 15 February 2008

Crystal Structure of Rab5-GDP Complex

Overview

Rab5 is a small GTPase that regulates early endosome fusion. We present, here the crystal structure of the Rab5 GTPase domain in complex with a GTP, analog and the C-terminal domain of effector Rabaptin5. The proteins form, a dyad-symmetric Rab5-Rabaptin5(2)-Rab5 ternary complex with a parallel, coiled-coil Rabaptin5 homodimer in the middle. Two Rab5 molecules bind, independently to the Rabaptin5 dimer using their switch and interswitch, regions. The binding does not involve the Rab complementarity-determining, regions. We also present the crystal structures of two distinct forms of, GDP-Rab5 complexes, both of which are incompatible with Rabaptin5 binding., One has a dislocated and disordered switch I but a virtually intact switch, II, whereas the other has its beta-sheet and both switch regions, reorganized. Biochemical and functional analyses show that the, crystallographically observed Rab5-Rabaptin5 complex also exists in, solution, and disruption of this complex by mutation abrogates endosome, fusion.

About this Structure

1TU4 is a Single protein structure of sequence from Homo sapiens with , and as ligands. Full crystallographic information is available from OCA.

Reference

Structural basis of Rab5-Rabaptin5 interaction in endocytosis., Zhu G, Zhai P, Liu J, Terzyan S, Li G, Zhang XC, Nat Struct Mol Biol. 2004 Oct;11(10):975-83. Epub 2004 Sep 19. PMID:15378032

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