1fvk
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THE 1.7 ANGSTROM STRUCTURE OF WILD TYPE DISULFIDE BOND FORMATION PROTEIN (DSBA)
OverviewOverview
DsbA, a 21-kDa protein from Escherichia coli, is a potent oxidizing, disulfide catalyst required for disulfide bond formation in secreted, proteins. The active site of DsbA is similar to that of mammalian protein, disulfide isomerases, and includes a reversible disulfide bond formed from, cysteines separated by two residues (Cys30-Pro31-His32-Cys33). Unlike most, protein disulfides, the active-site disulfide of DsbA is highly reactive, and the oxidized form of DsbA is much less stable than the reduced form at, physiological pH. His32, one of the two residues between the active-site, cysteines, is critical to the oxidizing power of DsbA and to the relative, instability of the protein in the oxidized form. Mutation of this single, residue to tyrosine, serine, or leucine results in a significant increase, in stability (of approximately 5-7 kcal/mol) of the oxidized His32, variants relative to the oxidized wild-type protein. Despite the dramatic, changes in stability, the structures of all three oxidized DsbA His32, variants are very similar to the wild-type oxidized structure, including, conservation of solvent atoms near the active-site residue, Cys30. These, results show that the His32 residue does not exert a conformational effect, on the structure of DsbA. The destabilizing effect of His32 on oxidized, DsbA is therefore most likely electrostatic in nature.
About this StructureAbout this Structure
1FVK is a Single protein structure of sequence from Escherichia coli. Known structural/functional Sites: and . Full crystallographic information is available from OCA.
ReferenceReference
Structural analysis of three His32 mutants of DsbA: support for an electrostatic role of His32 in DsbA stability., Guddat LW, Bardwell JC, Glockshuber R, Huber-Wunderlich M, Zander T, Martin JL, Protein Sci. 1997 Sep;6(9):1893-900. PMID:9300489
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