5hfk

CRYSTAL STRUCTURE OF A GLUTATHIONE S-TRANSFERASE PROTEIN FROM ESCHERICHIA COLI OCh 157:H7 STR. SAKAI (ECs3186, TARGET EFI-507414) WITH BOUND GLUTATHIONE

spinqualitylabelsall models 5hfk, resolution 1.55Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 5hfk is a 2 chain structure with sequence from Ecoli. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: GSH Gene: yfcG, b2302, JW2299 (ECOLI) Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [YFCG_ECOLI] Exhibits a very robust glutathione (GSH)-dependent disulfide-bond reductase activity toward the model substrate, 2-hydroxyethyl disulfide; the actual physiological substrates are not known. Has also a low GSH-dependent hydroperoxidase activity toward cumene hydroperoxide, but does not reduce H(2)O(2), tert-butyl hydroperoxide, benzyl peroxide, or lauroyl peroxide. Exhibits little or no GSH transferase activity with most typical electrophilic substrates, and has no detectable transferase activity using glutathionylspermidine (GspSH) as the nucleophilic substrate. Is involved in defense against oxidative stress, probably via its peroxidase activity. Publication Abstract from PubMed The crystal structure (1.50 A resolution) and biochemical properties of the GSH transferase homologue, YghU, from Escherichia coli reveal that the protein is unusual in that it binds two molecules of GSH in each active site. The crystallographic observation is consistent with biphasic equilibrium binding data that indicate one tight (K(d1) = 0.07 +/- 0.03 mM) and one weak (K(d2) = 1.3 +/- 0.2 mM) binding site for GSH. YghU exhibits little or no GSH transferase activity with most typical electrophilic substrates but does possess a modest catalytic activity toward several organic hydroperoxides. Most notably, the enzyme also exhibits disulfide-bond reductase activity toward 2-hydroxyethyl disulfide [k(cat) = 74 +/- 6 s(-1), and k(cat)/K(M)(GSH) = (6.6 +/- 1.3) x 10(4) M(-1) s(-1)] that is comparable to that previously determined for YfcG. A superposition of the structures of the YghU.2GSH and YfcG.GSSG complexes reveals a remarkable structural similarity of the active sites and the 2GSH and GSSG molecules in each. We conclude that the two structures represent reduced and oxidized forms of GSH-dependent disulfide-bond oxidoreductases that are distantly related to glutaredoxin 2. The structures and properties of YghU and YfcG indicate that they are members of the same, but previously unidentified, subfamily of GSH transferase homologues, which we suggest be called the nu-class GSH transferases. Structure and function of YghU, a nu-class glutathione transferase related to YfcG from Escherichia coli.,Stourman NV, Branch MC, Schaab MR, Harp JM, Ladner JE, Armstrong RN Biochemistry. 2011 Feb 22;50(7):1274-81. Epub 2011 Jan 24. PMID:21222452 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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