1OIX

X-ray structure of the small G protein Rab11a in complex with GDP and Pi

Summary for 1OIX

• Entry DOI: 10.2210/pdb1oix/pdb
• Related: 1OIV 1OIW
• Descriptor: RAS-RELATED PROTEIN RAB-11A, GUANOSINE-5'-DIPHOSPHATE, PHOSPHATE ION, ... (6 entities in total)
• Functional Keywords: small g protein, intracellular trafficking, gtp-binding, lipoprotein, prenylation, protein transport
• Biological source: HOMO SAPIENS (HUMAN)
• Total number of polymer chains: 1
• Total formula weight: 22123.19

Authors

Pasqualato, S.,Senic-Matuglia, F.,Renault, L.,Goud, B.,Salamero, J.,Cherfils, J. (deposition date: 2003-06-26, release date: 2005-01-25, Last modification date: 2023-12-13)

Primary citation

Pasqualato, S.,Cherfils, J.
Crystallographic Evidence for Substrate-Assisted GTP Hydrolysis by a Small GTP Binding Protein
Structure, 13:533-, 2005

PubMed Abstract: GTP hydrolysis by small GTP binding proteins of the Ras superfamily is a universal reaction that controls multiple cellular regulations. Its enzymic mechanism has been the subject of long-standing debates as to the existence/identity of the general base and the electronic nature of its transition state. Here we report the high-resolution crystal structure of a small GTP binding protein, Rab11, solved in complex with GDP and Pi. Unexpectedly, a Pi oxygen and the GDP-cleaved oxygen are located less than 2.5 A apart, suggesting that they share a proton, likely in the form of a low-barrier hydrogen bond. This implies that the gamma-phosphate of GTP was protonated; hence, that GTP acts as a general base. Furthermore, this interaction should establish at, and stabilize, the transition state. Altogether, we propose a revised model for the GTPase reaction that should reconcile earlier models into a unique substrate-assisted mechanism.

PubMed: 15837192
DOI: 10.1016/J.STR.2005.01.014

Experimental method

X-RAY DIFFRACTION (1.7 Å)