The Number of Nucleotide Binding Sites in Cytochrome C Oxidase

Rieger, T.; Napiwotzki, Jörg; Hüther, Fritz-Joachim; Kadenbach, Bernhard

doi:10.1006/bbrc.1995.2742

Cited by 23 publications

(20 citation statements)

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“…The function of 6 further ATP binding sites in COX of bovine heart and 6 ATP binding sites in COX of bovine liver [18] remains to be established. These include an ATP binding site localized at the C-terminal domain of subunit Via of COX from yeast, bovine heart and bovine liver [19].…”

Section: Discussionmentioning

confidence: 99%

Regulation of the H⁺/e⁻ stoichiometry of cytochrome c oxidase from bovine heart by intramitochondrial ATP/ADP ratios

1996

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This paper describes the effect of intramitochondriai ATP/ADP ratios on the H+/e -stoiehiometry of reconstituted eytoehrome c oxidase (COX) from bovine heart. At 100% intraliposomal ATP the H+/e -stuiehiometry of the reconstituted enzyme is decreased to half of the value measured below 98% intraliposomai ATP (above 2% ADP), while it remains constant up to 100% ADP. The decrease is obtuined with different COX preparations, independent of the absolute value of the H+/e -stolehiometry. Decrease of H+/e -stolehiometry is prevented by preincubation of the enzyme with a tissue-specific monocional antibody to subunit VIa-H (heart-type). Tissuespecific regulation of the efficiency of energy transduetion in COX of muscle mituehondria could have a physiological function in maintaining the body temperature at rest or sleep, i.e. at low ATP expenditure.

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Section: Discussionmentioning

confidence: 99%

Regulation of the H⁺/e⁻ stoichiometry of cytochrome c oxidase from bovine heart by intramitochondrial ATP/ADP ratios

1996

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“…It has been proposed that the nuclear encoded subunits of COX affect the catalytic function of the mitochondrial encoded subunits by binding allosteric effectors such as substrates, cofactors, ions, nucleotides and hormones [48]. Specifically, ATP has been shown to bind to two subunits of bovine heart COX, including subunit IV [49] and to six or seven subunits of COX from bovine liver or heart, respectively, including subunit IV [50]. As well, there is evidence indicating that the yeast homologue of subunit IV, subunit V, may regulate catalysis and modulate the function of the holoenzyme [51].…”

Section: Discussionmentioning

confidence: 99%

Mitochondrial cytochrome c oxidase subunit IV is phosphorylated by an endogenous kinase

Steenaart

Shore

1997

FEBS Letters

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This study was undertaken to identify novel mitochondrial membrane proteins that are potential targets for phosphorylation. Mitochondrial membranes were incubated in the presence of [y-32 P!ATP and the Triton X-114 extractable protein was subjected to ion-exchange and polyacrylamide gel chromatography to purify a major phosphorylated protein of approximately 17000 Da. The determined peptide sequence of the purified phosphoprotein corresponded to a segment of cytochrome c oxidase subunit IV, an inner membrane protein of 17160 Da. The identity of the phosphoprotein was confirmed by two-dimensional electrophoresis and Western blotting. The results identify mitochondrial cytochrome c oxidase subunit IV as a protein which is phosphorylated by an endogenous kinase.

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“…In addition, quantitative titrations with a uorescent ATP analogue (TNP-ATP) have demonstrated two ATP binding sites per monomer of COX isolated from bovine heart and liver (39) and from yeast (40). This number of sites has been recently reevaluated for mammalian COX to be three (36). In addition, many efforts have been made to localize the binding sites for adenylic nucleotides on the COX subunits.…”

Section: Interaction Of Adenylic Nucleotides On Coxmentioning

confidence: 99%

“…In earlier studies using 8-azido[°3 2 P]ATP, labeling was found for bovine COX in subunit IV along with subunits VIIa, b, c-and VIII (not resolved on the gel system used) (41)(42). However, later studies were unable to repeat this relatively speci c labeling and almost every subunit of the complex was labeled (31,36,43). More recently, covalent photolabeling using 2-azido[°3 2 P]ATP con rmed the presence of an ATP-binding site on subunit VIa of isolated COX from yeast, beef heart, and kidney (40).…”

Section: Interaction Of Adenylic Nucleotides On Coxmentioning

confidence: 99%

Regulation of Cytochrome c Oxidase by Adenylic Nucleotides. Is Oxidative Phosphorylation Feedback Regulated by its End‐Products?

Beauvoit¹,

Rigoulet²

2001

IUBMB Life

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SummaryCytochrome c oxidase, which catalyzes an irreversible step of the respiratory chain, is one of the rate-controlling steps of oxidative phosphorylation on isolated mitochondria. The rate of electron transfer through the complex is primarily controlled by the associated thermodynamic forces, i.e., the span in redox potential between oxygen and cytochrome c and the protonmotive force. However, the electron ux also depends on the various kinetic effectors, including adenylic nucleotides. Although the number of binding sites for ATP and ADP on cytochrome oxidase is still a matter of debate, experiments performed on the solubilized and reconstituted enzyme provide strong functional evidence that the mammalian cytochrome c oxidase binds adenylic nucleotides on both sides of the inner membrane. These effects include modi cation in cytochrome c af nity, allosteric inhibition and changes in proton pumping ef ciency. Immunological studies have pointed out the role of subunit IV and that of an ATP-binding protein, subunit VIa, in these kinetic regulations. In yeast, the role of the nuclear-encoded subunits in assembly and regulation of the cytochrome c oxidase has been further substantiated by using gene-disruption analysis. Using a subunit VIa-null mutant, the consequences of the ATP regulation on oxidative phosphorylation have been further investigated on isolated mitochondria. Taken together, the data demonstrate that there are multiple regulating sites for ATP on the yeast cytochrome oxidase with respect to the location (matrix versus cytosolic side), kinetic effect (activation versus inhibition) and consequence on the ow-force relationships. The question is therefore raised as to the

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The Number of Nucleotide Binding Sites in Cytochrome C Oxidase

Cited by 23 publications

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Regulation of the H⁺/e⁻ stoichiometry of cytochrome c oxidase from bovine heart by intramitochondrial ATP/ADP ratios

Regulation of the H⁺/e⁻ stoichiometry of cytochrome c oxidase from bovine heart by intramitochondrial ATP/ADP ratios

Mitochondrial cytochrome c oxidase subunit IV is phosphorylated by an endogenous kinase

Regulation of Cytochrome c Oxidase by Adenylic Nucleotides. Is Oxidative Phosphorylation Feedback Regulated by its End‐Products?

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The Number of Nucleotide Binding Sites in Cytochrome C Oxidase

Cited by 23 publications

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Regulation of the H+/e− stoichiometry of cytochrome c oxidase from bovine heart by intramitochondrial ATP/ADP ratios

Regulation of the H+/e− stoichiometry of cytochrome c oxidase from bovine heart by intramitochondrial ATP/ADP ratios

Mitochondrial cytochrome c oxidase subunit IV is phosphorylated by an endogenous kinase

Regulation of Cytochrome c Oxidase by Adenylic Nucleotides. Is Oxidative Phosphorylation Feedback Regulated by its End‐Products?

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Regulation of the H⁺/e⁻ stoichiometry of cytochrome c oxidase from bovine heart by intramitochondrial ATP/ADP ratios

Regulation of the H⁺/e⁻ stoichiometry of cytochrome c oxidase from bovine heart by intramitochondrial ATP/ADP ratios