Three Molecules of Ubiquinone Bind Specifically to Mitochondrial Cytochrome bc 1Complex
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چکیده
منابع مشابه
Three molecules of ubiquinone bind specifically to mitochondrial cytochrome bc1 complex.
Bifurcated electron flow to high potential "Rieske" iron-sulfur cluster and low potential heme b(L) is crucial for respiratory energy conservation by the cytochrome bc(1) complex. The chemistry of ubiquinol oxidation has to ensure the thermodynamically unfavorable electron transfer to heme b(L). To resolve a central controversy about the number of ubiquinol molecules involved in this reaction, ...
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Mitochondrial succinate-ubiquinone reductase is composed of two parts, a water-soluble succinate dehydrogenase and a two-polypeptide membrane-anchoring protein fraction (QPs). The larger polypeptide of QPs is believed to be associated with cytochrome bas, (QPsl). The structure of QPsl was studied by immunochemistry and molecular cloning and sequencing. Antibodies against QPsl were raised in r...
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Cytochrome b was identified as one of the ubiquinone-binding proteins in bovine heart mitochondrial ubiquinol-cytochrome c reductase by photoaffinity labeling using 3-azido-2-methyl-5-methoxy-6-(3,7-dimethyl[3H]-octyl)-1,4-benzoquinone ([3H]azido-Q). The [3H]azido-Q-labeled cytochrome b protein was purified to homogeneity from the azido-Q-labeled ubiquinol-cytochrome c reductase by a procedure ...
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We have examined the pre-steady state reduction kinetics of the Saccharomyces cerevisiae cytochrome bc(1) complex by menaquinol in the presence and absence of endogenous ubiquinone to elucidate the mechanism of triphasic cytochrome b reduction. With cytochrome bc(1) complex from wild type yeast, cytochrome b reduction was triphasic, consisting of a rapid partial reduction phase, an apparent par...
متن کاملThe indispensability of phospholipid and ubiquinone in mitochondrial electron transfer from succinate to cytochrome c.
The indispensability of phospholipid and ubiquinone (Q) in mitochondrial electron transfer was studied by depleting phospholipid and Q in succinate-cytochrome c reductase and then replenishing the depleted enzyme. More than 90% of phospholipid and Q was removed by repeated ammonium sulfate-cholate fractionation. The depleted succinate-cytochrome c reductase showed no enzymatic activity for succ...
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ژورنال
عنوان ژورنال: Journal of Biological Chemistry
سال: 2001
ISSN: 0021-9258
DOI: 10.1074/jbc.c100365200