Linked Life Data

9535897

Source:http://linkedlifedata.com/resource/pubmed/id/9535897

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
15
pubmed:dateCreated
1998-5-14
pubmed:abstractText
The crystal structure of the bovine Rieske iron-sulfur protein indicates a sulfur atom (S-1) of the iron-sulfur cluster and the sulfur atom (Sgamma) of a cysteine residue that coordinates one of the iron atoms form hydrogen bonds with the hydroxyl groups of Ser-163 and Tyr-165, respectively. We have altered the equivalent Ser-183 and Tyr-185 in the Saccharomyces cerevisiae Rieske iron-sulfur protein by site-directed mutagenesis of the iron-sulfur protein gene to examine how these hydrogen bonds affect the midpoint potential of the iron-sulfur cluster and how changes in the midpoint potential affect the activity of the enzyme. Eliminating the hydrogen bond from the hydroxyl group of Ser-183 to S-1 of the cluster lowers the midpoint potential of the cluster by 130 mV, and eliminating the hydrogen bond from the hydroxyl group of Tyr-185 to Sgamma of Cys-159 lowers the midpoint potential by 65 mV. Eliminating both hydrogen bonds has an approximately additive effect, lowering the midpoint potential by 180 mV. Thus, these hydrogen bonds contribute significantly to the positive midpoint potential of the cluster but are not essential for its assembly. The activity of the bc1 complex decreases with the decrease in midpoint potential, confirming that oxidation of ubiquinol by the iron-sulfur protein is the rate-limiting partial reaction in the bc1 complex, and that the rate of this reaction is extensively influenced by the midpoint potential of the iron-sulfur cluster.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
10
pubmed:volume
273
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
9085-93
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed-meshheading:9535897-Amino Acid Sequence, pubmed-meshheading:9535897-Amino Acid Substitution, pubmed-meshheading:9535897-Animals, pubmed-meshheading:9535897-Catalysis, pubmed-meshheading:9535897-Cattle, pubmed-meshheading:9535897-Computer Simulation, pubmed-meshheading:9535897-Disulfides, pubmed-meshheading:9535897-Electron Transport Complex III, pubmed-meshheading:9535897-Hydrogen Bonding, pubmed-meshheading:9535897-Iron, pubmed-meshheading:9535897-Iron-Sulfur Proteins, pubmed-meshheading:9535897-Kinetics, pubmed-meshheading:9535897-Models, Chemical, pubmed-meshheading:9535897-Models, Molecular, pubmed-meshheading:9535897-Molecular Sequence Data, pubmed-meshheading:9535897-Mutagenesis, Site-Directed, pubmed-meshheading:9535897-Oxidation-Reduction, pubmed-meshheading:9535897-Protein Structure, Secondary, pubmed-meshheading:9535897-Recombinant Proteins, pubmed-meshheading:9535897-Saccharomyces cerevisiae, pubmed-meshheading:9535897-Sequence Alignment, pubmed-meshheading:9535897-Serine, pubmed-meshheading:9535897-Sulfur, pubmed-meshheading:9535897-Tyrosine
pubmed:year
1998
pubmed:articleTitle
Alteration of the midpoint potential and catalytic activity of the rieske iron-sulfur protein by changes of amino acids forming hydrogen bonds to the iron-sulfur cluster.
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., Research Support, Non-U.S. Gov't