Linked Life Data

9268296

Source:http://linkedlifedata.com/resource/pubmed/id/9268296

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
35
pubmed:dateCreated
1997-10-2
pubmed:abstractText
Disulfide oxidoreductases are structurally related proteins that share the thioredoxin fold and a catalytic disulfide bond that is located at the N terminus of an alpha-helix. The different redox potentials of these enzymes varying from -270 mV for thioredoxin to -125 mV for DsbA have been attributed to the lowered pKa values of their nucleophilic, active-site cysteines and the difference in thermodynamic stability between their oxidized and reduced forms (DeltaDeltaGox/red). The lowered pKa of the nucleophilic cysteine thiols was proposed to result from favorable interactions with the helix dipole and charged residues in their vicinity. In this study, we have eliminated all charged residues in the neighborhood of the active-site disulfide of DsbA from Escherichia coli to analyze their contribution to the physicochemical properties of the protein. We show that the conserved charge network among residues Glu24, Glu37, and Lys58 stabilizes the oxidized form of DsbA and thus does not cause the high redox potential of the enzyme. The pKa values of the nucleophilic cysteine (Cys30) and the redox potentials of the DsbA variants E24Q, E37Q, K58M, E24Q/K58M, E37Q/K58M, E24Q/E37Q, E24Q/E37Q/K58M, and E24Q/E37Q/E38Q/K58M are similar to those of DsbA wild type. The redox potentials of the variants neither correlate with the Cys30 pKa values nor with the DeltaDeltaGox/red values, demonstrating that the relationship between these parameters is far more complex than previously thought.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
29
pubmed:volume
272
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
21692-9
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:year
1997
pubmed:articleTitle
Elimination of all charged residues in the vicinity of the active-site helix of the disulfide oxidoreductase DsbA. Influence of electrostatic interactions on stability and redox properties.
pubmed:affiliation
Institut für Molekularbiologie und Biophysik, Eidgenössische Technische Hochschule-Hönggerberg, CH-8093 Zürich, Switzerland. jacobi@mol.biol.ethz.ch
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't