1acv
From Proteopedia
(New page: 200px<br /><applet load="1acv" size="450" color="white" frame="true" align="right" spinBox="true" caption="1acv, resolution 1.9Å" /> '''DSBA MUTANT H32S'''<b...) |
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| - | [[Image:1acv.gif|left|200px]]<br /><applet load="1acv" size=" | + | [[Image:1acv.gif|left|200px]]<br /><applet load="1acv" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1acv, resolution 1.9Å" /> | caption="1acv, resolution 1.9Å" /> | ||
'''DSBA MUTANT H32S'''<br /> | '''DSBA MUTANT H32S'''<br /> | ||
==Overview== | ==Overview== | ||
| - | DsbA, a 21-kDa protein from Escherichia coli, is a potent oxidizing | + | 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 Structure== | ==About this Structure== | ||
| - | 1ACV is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Full crystallographic information is available from [http:// | + | 1ACV is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1ACV OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Escherichia coli]] | [[Category: Escherichia coli]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Guddat, L | + | [[Category: Guddat, L W.]] |
| - | [[Category: Martin, J | + | [[Category: Martin, J L.]] |
[[Category: disulfide oxidoreductase]] | [[Category: disulfide oxidoreductase]] | ||
[[Category: redox-active center]] | [[Category: redox-active center]] | ||
[[Category: thioredoxin fold]] | [[Category: thioredoxin fold]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 11:43:11 2008'' |
Revision as of 09:43, 21 February 2008
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DSBA MUTANT H32S
Overview
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 Structure
1ACV is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.
Reference
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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