The Binding of Carbon Monoxide to Cytochrome c Oxidase

Wever, R.; Drooge, J.H. Van; Muijsers, Anton O.; Gelder, B.F. Van; Bakker, Evert P.

doi:10.1111/j.1432-1033.1977.tb11301.x

Cited by 54 publications

(22 citation statements)

References 32 publications

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“…General agreement on the assignment of the infrared absorbance bands of cytochrome oxidase (9, 16) largely, if not completely, to the copper atoms seems established (23,24); the assignment of this band to divalent copper is well founded upon reductive titrations of the oxidized or resting oxidase (25). These data also suggest the further assignment of cupric copper associated with heme a3 in compound C at 744 nm and in compound B at 795 nm.…”

Section: Discussionsupporting

confidence: 60%

Oxygen intermediates and mixed valence states of cytochrome oxidase: infrared absorption difference spectra of compounds A, B, and C of cytochrome oxidase and oxygen.

Chance¹,

Leigh²

1977

Proc. Natl. Acad. Sci. U.S.A.

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A study of the near-infrared absorption spectra of three oxygen compounds of membrane-bound cytochrome oxidase (ferrocytochrome c:oxygen oxidoreductase; EC 1.9.3.1) shows that the formation of compound A (oxycytochrome oxidase) causes no significant infrared absorbance changes at -1030. At -640, the formation of compound C from the mixed-valence state of the oxidase leads to increased absorption at [740][741][742][743][744][745][746][747][748][749][750] Three compounds-A, B, and C-are formed in the reaction of cytochrome oxidase with oxygen at significant concentrations at very low temperatures. They form at rates that can be extrapolated with consistency to agree with the rates of electron transfer in cytochrome oxidase as measured at room temperature in the solubilized (1, 2) and membrane-bound (3, 4) enzyme. Thus, compounds A and B appear to be functional intermediates in the oxidase reaction and seem to differ significantly from the various "oxygenated" species of cytochrome oxidase found in the presence of dithionite and oxygen (5,6) and not observed at low temperatures.The most unusual, and in many ways the most interesting, compound is C (3, 4), formed from the partially oxidized or mixed valence state oxidase (7,8) in which cytochrome a and its associated copper (9) are oxidized prior to reaction with oxygen. Cytochrome a3 reduced (and bound to CO) and its associated copper atom is presumed to remain reduced as well (7,8 This communication describes the unique infrared absorption spectra of compound C in relation to those of compounds A and B, and proposes a new structure for compound C. METHODS A split-beam, split photolysis spectrophotometer (10) was adapted to precise scanning of the infrared region of the cytochrome oxidase spectrum from 700 to 900 nm. Baseline errors in this spectral region were recorded in the digital memory. The cuvette was then illuminated on half its area to cause photolysis of the a32+-CO compound and initiation of the reaction with oxygen in the illuminated portion of the sample; the unilluminated portion still contained a32+.CO. The computer memory corrected for the baseline errors and gave the corrected difference spectrum between the two portions of the sample.Since frozen samples were usually used, no septum between the two parts was needed. No nonspecific light-scattering change was observed in the frozen sample held at constant temperature.Frozen-thawed beef heart mitochondria prepared according to the method of L6w and Vallin (11) (kindly donated by C. P. Lee) were suspended in 30% ethylene glycol (freezing point, -22°), 0.1 M mannitol, and 5 mM Tris-sulfate buffer, pH 7.4. The mitochondria, at approximately 30 mg of protein per ml, supplemented with 5 mM glutamate and 5 mM succinate, were saturated with CO, supplemented with 30% ethylene glycol by volume, resaturated with CO, and maintained at 00 [or, for longer storage, at -200, at which the preparation is stable for at least a week (12)]. Electron transport from succinate to oxygen is inhibited by about ...

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Section: Discussionsupporting

confidence: 60%

Oxygen intermediates and mixed valence states of cytochrome oxidase: infrared absorption difference spectra of compounds A, B, and C of cytochrome oxidase and oxygen.

Chance¹,

Leigh²

1977

Proc. Natl. Acad. Sci. U.S.A.

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“…(4) Copper is the major, if not only, contributor to the 830nm traces (Aasa et al, 1976;Wever et al, 1977).…”

Section: Resultsmentioning

confidence: 99%

The mechanism of reaction of ferricyanide-pretreated mixed-valence-state membrane-bound cytochrome oxidase with oxygen at 173 K

Clore¹,

Chance²

1978

Biochemical Journal

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1. The results of non-linear optimization studies on the mechanism of reaction of ferricyanide-pretreated mixed-valence-state cytochrome oxidase with 02 at 173 K are presented. The analysis is carried out on data obtained by means of dual-wavelength multi-channel spectroscopy at four wavelength pairs (444-463 nm, 604-630nm, 608-630nm and 830-940nm) and at two 02 concentrations (360,uM and 520AM). The only model that satisfies the triple requirement of a standard deviation within the standard error of the experimental data, a random distribution of residuals and good determination of the optimized parameters, is a three-intermediate sequential mechanism. 2. On the basis of the optimized values of the relative absorption coefficients of the intermediates at each wavelength obtained from the present paper together with data from optical wavelength scanning and e.p.r. spectroscopy obtained by low-temperature trapping studies, the possible valence states of the metal centres in each of the intermediates are discussed.

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“…These ligands cause the simultaneous disappearence of both the resonances at g 3.27 and g 3.36, the low-spin heine signal with gz 2.6, gy 2.2, and gx 1.86 as well as the highspin heme signals. As proposed [10,[14][15][16], these ligand-induced changes are likely to be due to an electron redistribution brought about by changes in the redox potentials of the heine and copper components in the enzyme upon binding of ligands to cytochrome a3.…”

Section: Discussionmentioning

confidence: 86%