1gzs

From Proteopedia

Revision as of 17:54, 30 March 2008

CRYSTAL STRUCTURE OF THE COMPLEX BETWEEN THE GEF DOMAIN OF THE SALMONELLA TYPHIMURIUM SOPE TOXIN AND HUMAN CDC42

Overview

The bacterial enteropathogen Salmonella typhimurium employs a type III secretion system to inject bacterial toxins into the host cell cytosol. These toxins transiently activate Rho family GTP-binding protein-dependent signaling cascades to induce cytoskeletal rearrangements. One of these translocated Salmonella toxins, SopE, can activate Cdc42 in a Dbl-like fashion despite its lack of sequence similarity to Dbl-like proteins, the Rho-specific eukaryotic guanine nucleotide exchange factors. To elucidate the mechanism of SopE-mediated guanine nucleotide exchange, we have analyzed the structure of the complex between a catalytic fragment of SopE and Cdc42. SopE binds to and locks the switch I and switch II regions of Cdc42 in a conformation that promotes guanine nucleotide release. This conformation is strikingly similar to that of Rac1 in complex with the eukaryotic Dbl-like exchange factor Tiam1. However, the catalytic domain of SopE has an entirely different architecture from that of Tiam1 and interacts with the switch regions via different amino acids. Therefore, SopE represents the first example of a non-Dbl-like protein capable of inducing guanine nucleotide exchange in Rho family proteins.

About this Structure

1GZS is a Protein complex structure of sequences from Homo sapiens and Salmonella typhimurium. Full crystallographic information is available from OCA.

Reference

Structural basis for the reversible activation of a Rho protein by the bacterial toxin SopE., Buchwald G, Friebel A, Galan JE, Hardt WD, Wittinghofer A, Scheffzek K, EMBO J. 2002 Jul 1;21(13):3286-95. PMID:12093730

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