1r8m

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spinqualitylabelsall models PDB ID 1r8m Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image
, resolution 1.70Å
Ligands:	and
Gene:	PSCD2, ARNO (Homo sapiens)
Coordinates:	save as pdb, mmCIF, xml

SEC7 DOMAIN OF THE ARF EXCHANGE FACTOR ARNO WITH BREFELDIN A-SENSITIZING MUTATIONS

Overview

Small GTP-binding (G) proteins are activated by GDP/GTP nucleotide exchange stimulated by guanine nucleotide exchange factors (GEFs). Nucleotide dissociation from small G protein-GEF complexes involves transient GDP-bound intermediates whose structures have never been described. In the case of Arf proteins, small G proteins that regulate membrane traffic in eukaryotic cells, such intermediates can be trapped either by the natural inhibitor brefeldin A or by charge reversal at the catalytic glutamate of the Sec7 domain of their GEFs. Here we report the crystal structures of these intermediates that show that membrane recruitment of Arf and nucleotide dissociation are separate reactions stimulated by Sec7. The reactions proceed through sequential rotations of the Arf.GDP core towards the Sec7 catalytic site, and are blocked by interfacial binding of brefeldin A and unproductive stabilization of GDP by charge reversal. The structural characteristics of the reaction and its modes of inhibition reveal unexplored ways in which to inhibit the activation of small G proteins.

About this Structure

1R8M is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.

Reference

Structural snapshots of the mechanism and inhibition of a guanine nucleotide exchange factor., Renault L, Guibert B, Cherfils J, Nature. 2003 Dec 4;426(6966):525-30. PMID:14654833

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