Linked Life Data

14622010

Source:http://linkedlifedata.com/resource/pubmed/id/14622010

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
46
pubmed:dateCreated
2003-11-18
pubmed:abstractText
The [2Fe-2S] cluster of the Rieske iron-sulfur protein is held between two loops of the protein that are connected by a disulfide bridge. We have replaced the two cysteines that form the disulfide bridge in the Rieske protein of Saccharomyces cerevisiae with tyrosine and leucine, and tyrosine and valine, to evaluate the effects of the disulfide bridge on assembly, stability, and thermodynamic properties of the Rieske iron-sulfur cluster. EPR spectra of the Rieske proteins lacking the disulfide bridge indicate the iron-sulfur cluster is assembled in the absence of the disulfide bridge, but there are significant shifts in all g values, indicating a change in the electronic structure of the [2Fe-2S] iron-sulfur center. In addition, the midpoint potential of the iron-sulfur cluster is lowered from 265 mV in the Rieske protein from wild-type yeast to 150 mV in the protein from the C164Y/C180L mutant and to 160 mV in the protein from the C164Y/C180V mutant. Ubiquinol-cytochrome c reductase activities of the bc(1) complexes with Rieske proteins lacking the disulfide bridge are less than 1% of the activity of the bc(1) complex from wild-type yeast, even though normal amounts of the iron-sulfur protein are present as judged by Western blot analysis. These activities are lower than the 105-115 mV decrease in the midpoint potential of the Rieske iron-sulfur cluster can account for. Pre-steady-state reduction of the bc(1) complexes with menadiol indicates that quinol is not oxidized through center P but is oxidized through center N. In addition, the levels of stigmatellin and UHDBT binding are markedly diminished, while antimycin binding is unaffected, in the bc(1) complexes with Rieske proteins lacking the disulfide bridge. Taken together, these results indicate that the ubiquinol oxidation site at center P is damaged in the bc(1) complexes with Rieske proteins lacking the disulfide bridge even though the iron-sulfur cluster is assembled into the Rieske protein.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
25
pubmed:volume
42
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
13637-45
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed-meshheading:14622010-Amino Acid Sequence, pubmed-meshheading:14622010-Amino Acid Substitution, pubmed-meshheading:14622010-Binding Sites, pubmed-meshheading:14622010-Blotting, Western, pubmed-meshheading:14622010-Cysteine, pubmed-meshheading:14622010-Disulfides, pubmed-meshheading:14622010-Electron Spin Resonance Spectroscopy, pubmed-meshheading:14622010-Electron Transport Complex III, pubmed-meshheading:14622010-Iron-Sulfur Proteins, pubmed-meshheading:14622010-Mitochondria, pubmed-meshheading:14622010-Models, Molecular, pubmed-meshheading:14622010-Molecular Sequence Data, pubmed-meshheading:14622010-Oxidation-Reduction, pubmed-meshheading:14622010-Potentiometry, pubmed-meshheading:14622010-Recombinant Proteins, pubmed-meshheading:14622010-Ubiquinone, pubmed-meshheading:14622010-Yeasts
pubmed:year
2003
pubmed:articleTitle
Elimination of the disulfide bridge in the Rieske iron-sulfur protein allows assembly of the [2Fe-2S] cluster into the Rieske protein but damages the ubiquinol oxidation site in the cytochrome bc1 complex.
pubmed:affiliation
Department of Biochemistry, Dartmouth Medical School, Hanover, New Hampshire 03755, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.