2z8j

Crystal Structure of Escherichia coli gamma-Glutamyltranspeptidase in Complex with Azaserine prepared in the dark

spinqualitylabelsall models 2z8j, resolution 2.05Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2z8j is a 4 chain structure with sequence from Escherichia coli. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.05Å Ligands: AZS Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function GGT_ECOLI Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed gamma-Glutamyltranspeptidase (GGT) catalyzes the cleavage of such gamma-glutamyl compounds as glutathione, and the transfer of their gamma-glutamyl group to water or to other amino acids and peptides. GGT is involved in a number of biological phenomena such as drug resistance and metastasis of cancer cells by detoxification of xenobiotics. Azaserine and acivicin are classical and irreversible inhibitors of GGT, but their binding sites and the inhibition mechanisms remain to be defined. We have determined the crystal structures of GGT from Escherichia coli in complex with azaserine and acivicin at 1.65 A resolution. Both inhibitors are bound to GGT at its substrate-binding pocket in a manner similar to that observed previously with the gamma-glutamyl-enzyme intermediate. They form a covalent bond with the O(gamma) atom of Thr391, the catalytic residue of GGT. Their alpha-carboxy and alpha-amino groups are recognized by extensive hydrogen bonding and charge interactions with the residues that are conserved among GGT orthologs. The two amido nitrogen atoms of Gly483 and Gly484, which form the oxyanion hole, interact with the inhibitors directly or via a water molecule. Notably, in the azaserine complex the carbon atom that forms a covalent bond with Thr391 is sp(3)-hybridized, suggesting that the carbonyl of azaserine is attacked by Thr391 to form a tetrahedral intermediate, which is stabilized by the oxyanion hole. Furthermore, when acivicin is bound to GGT, a migration of the single and double bonds occurs in its dihydroisoxazole ring. The structural characteristics presented here imply that the unprecedented binding modes of azaserine and acivicin are conserved in all GGTs from bacteria to mammals and give a new insight into the inhibition mechanism of glutamine amidotransferases by these glutamine antagonists. Crystal structures of Escherichia coli gamma-glutamyltranspeptidase in complex with azaserine and acivicin: novel mechanistic implication for inhibition by glutamine antagonists.,Wada K, Hiratake J, Irie M, Okada T, Yamada C, Kumagai H, Suzuki H, Fukuyama K J Mol Biol. 2008 Jul 4;380(2):361-72. Epub 2008 May 12. PMID:18555071 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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