2d32 | pdb_00002d32

Crystal Structure of Michaelis Complex of gamma-Glutamylcysteine Synthetase

spinqualitylabelsall models 2d32, resolution 2.40Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2d32 is a 4 chain structure with sequence from "bacillus_coli"_migula_1895 "bacillus coli" migula 1895. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: ANP, CYS, GLU, MG Related: 1va6, 1v4g, 2d33 Gene: gshI ("Bacillus coli" Migula 1895) Activity: Glutamate--cysteine ligase, with EC number 6.3.2.2 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT 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-glutamylcysteine synthetase (gammaGCS), a rate-limiting enzyme in glutathione biosynthesis, plays a central role in glutathione homeostasis and is a target for development of potential therapeutic agents against parasites and cancer. We have determined the crystal structures of Escherichia coli gammaGCS unliganded and complexed with a sulfoximine-based transition-state analog inhibitor at resolutions of 2.5 and 2.1 A, respectively. In the crystal structure of the complex, the bound inhibitor is phosphorylated at the sulfoximido nitrogen and is coordinated to three Mg2+ ions. The cysteine-binding site was identified; it is formed inductively at the transition state. In the unliganded structure, an open space exists around the representative cysteine-binding site and is probably responsible for the competitive binding of glutathione. Upon inhibitor binding, the side chains of Tyr-241 and Tyr-300 turn, forming a hydrogen-bonding triad with the carboxyl group of the inhibitor's cysteine moiety, allowing this moiety to fit tightly into the cysteine-binding site with concomitant accommodation of its side chain into a shallow pocket. This movement is caused by a conformational change of a switch loop (residues 240-249). Based on this crystal structure, the cysteine-binding sites of mammalian and parasitic gammaGCSs were predicted by multiple sequence alignment, although no significant sequence identity exists between the E. coli gammaGCS and its eukaryotic homologues. The identification of this cysteine-binding site provides important information for the rational design of novel gammaGCS inhibitors. Crystal structure of gamma-glutamylcysteine synthetase: insights into the mechanism of catalysis by a key enzyme for glutathione homeostasis.,Hibi T, Nii H, Nakatsu T, Kimura A, Kato H, Hiratake J, Oda J Proc Natl Acad Sci U S A. 2004 Oct 19;101(42):15052-7. Epub 2004 Oct 11. PMID:15477603 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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