Linked Life Data

7783200

Source:http://linkedlifedata.com/resource/pubmed/id/7783200

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1995-7-18
pubmed:abstractText
The disulphide active sites of thioredoxin and DsbA are known to possess a high degree of structural homology. However, DsbA is a much stronger oxidant than thioredoxin. The redox potential difference between DsbA and thioredoxin has been measured to be 160 mV, equivalent to a shift of 15.4 kJ/mol in the reduced/oxidised equilibrium. Electrostatics calculations have been used to study the relative stabilities of the reduced forms of the two proteins. Model calculations suggest that much of the redox potential difference between DsbA and thioredoxin arises form altered stabilisation of the exposed and ionised thiolates of the reduced forms, supporting suggestions previously made on the basis of experimental studies. The calculations have been used to construct a molecular model for the difference in thiolate stabilisation. Although specific interactions, such as thiolate-NH 35 (thioredoxin)/33 (DsbA), provide substantial stabilisation in each reduced protein, the difference between thioredoxin and DsbA is predicted to reside in several side-chain and main-chain groups acting in concert. Residues H32 and Q97 in DsbA are predicted to contribute, along with substantial regions of the polypeptide backbone in the protein domain which is common to DsbA and thioredoxin. Increased thiolate stabilisation by the peptide dipoles is suggested to arise from altered main-chain disposition, and the effect of the additional protein domain of DsbA on the electric field. Peptide dipoles in a region of about 20 residues close to the active site disulphide are predicted to contribute significantly to the redox potential difference.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0022-2836
pubmed:author
pubmed:issnType
Print
pubmed:day
2
pubmed:volume
249
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
376-87
pubmed:dateRevised
2009-9-29
pubmed:meshHeading
pubmed:year
1995
pubmed:articleTitle
A molecular model for the redox potential difference between thioredoxin and DsbA, based on electrostatics calculations.
pubmed:affiliation
Biological Laboratory, University of Kent Canterbury, UK.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, Non-U.S. Gov't