Linked Life Data

1850617

Source:http://linkedlifedata.com/resource/pubmed/id/1850617

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
17
pubmed:dateCreated
1991-5-31
pubmed:abstractText
To understand the determinants of redox potential and protein stability in c-type cytochromes, we have characterized two mutations to a highly conserved tyrosine group, tyrosine-75, of Rhodobacter capsulatus cytochrome c2. Mutant Y75F was designed to test the importance of the tyrosine hydroxyl group to the typically high redox potentials of the cytochromes c2 while maintaining a hydrophobic core. Mutant Y75C was designed to test the importance of a large hydrophobic group to redox potential by replacing an aromatic group with a small nonpolar group. Both mutants exhibit spectral and redox properties indicating that their heme environments have been perturbed. The kinetics of reduction by lumiflavin semiquinone and photooxidation by Rhodobacter sphaeroides photosynthetic reaction centers have been used to demonstrate that both mutants are structurally analogous to the wild-type protein at the active site of electron transfer. Different degrees of relative stability of the mutants toward a denaturant have been observed with the order being Y75C less than wt less than Y75F in the oxidized state and Y75C less than Y75F less than wt in the reduced state. These results are discussed in light of the recent structure determination of the R. capsulatus wild-type ferrocytochrome c2 to suggest that R. capsulatus tyrosine-75, or its equivalent in other species, is part of a conserved hydrogen-bonding network which plays an important role in maintaining high redox potentials and protein stability of cytochromes c in general.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
30
pubmed:volume
30
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
4119-25
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1991
pubmed:articleTitle
Importance of a conserved hydrogen-bonding network in cytochromes c to their redox potentials and stabilities.
pubmed:affiliation
Department of Biochemistry, University of Arizona, Tucson 85721.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.