3c8e
From Proteopedia
Crystal Structure Analysis of yghU from E. Coli
Structural highlights
Function[YGHU_ECOLI] Exhibits a robust glutathione (GSH)-dependent disulfide-bond reductase activity toward the model substrate, 2-hydroxyethyl disulfide; the actual physiological substrates are not known. Also displays a modest GSH-dependent peroxidase activity toward several organic hydroperoxides, such as cumene hydroperoxide and linoleic acid 13(S)-hydroperoxide, but does not reduce H(2)O(2) or tert-butyl hydroperoxide at appreciable rates. Exhibits little or no GSH transferase activity with most typical electrophilic substrates, and has no detectable transferase activity toward 1-chloro-2,4-dinitrobenzene (CDNB) with glutathionylspermidine (GspSH) as the nucleophilic substrate. 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 PubMedThe 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[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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