Linked Life Data

7548152

Source:http://linkedlifedata.com/resource/pubmed/id/7548152

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1995-11-3
pubmed:abstractText
Although 13 lysines of horse cytochrome c are invariant, and three more are extremely conserved, the modification of their side-chain epsilon-amino groups by beta-thiopropionylation caused important changes in protein properties for only three of them; lysines 72,73 and 79. Optical spectroscopy, electron and nuclear paramagnetic resonance, electron spin echo envelope modulation, and molecular weight studies, as well as the unique features of their reaction with cytochrome-c oxidase, indicate that in the oxidized state the modification of these lysines resulted in equilibria between two different states of iron ligation: the native state, in which the metal is coordinated by the methionine-80 sulfur, and a new state in which this ligand is displaced by the sulfhydryl groups of the elongated side chains. The reduction potentials of the TP Lys-72 and the TP Lys-79 derivatives were 201 and 196 millivolt, respectively, indicating that the equilibria favored the sulfhydryl ligated state by 1.5 and 1.7 kcal/mol, respectively. In the ferric state, the protein modified at lysine 72 remained stable as a monomer, but that modified at lysine 73 dimerized rapidly through disulfide bond formation, while the TP Lys-79 cytochrome c dimerized with a half-time of approx. 3 h, both recovering the native-like iron ligation. By contrast, in the ferrous state the monomeric state and the native ligation were preserved in all cases, indicating that the affinity of the cytochrome-c ferrous iron for the methionine-80 sulfur is particularly strong. The dimerized derivatives lost most, but not all, of the capability of the native protein for electron transfer from ascorbate-TMPD to cytochrome-c oxidase.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0006-3002
pubmed:author
pubmed:issnType
Print
pubmed:day
27
pubmed:volume
1252
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
103-13
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1995
pubmed:articleTitle
A chemical modification of cytochrome-c lysines leading to changes in heme iron ligation.
pubmed:affiliation
Department of Biological Sciences, University of Illinois at Chicago 60607, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.