Abstract
Carbon monoxide bound to iron or copper in substrate-reduced mitochondrial cytochrome c oxidase (ferrocytochrome c:oxygen oxidoreductase, EC 1.9.3.1) from beef heart has been used to explore the structural interaction of the a3 heme-copper pocket at 15 K and 80 K in the dark and in the presence of visible light. The vibrational absorptions of CO measured by a Fourier transform infrared interferometer occur in the dark at 1963 cm-1, with small absorptions near 1952 cm-1, and are due to a3 heme--CO complexes. These disappear in strong visible light and are replaced by a major absorption at 2062 cm-1 and a minor one at 2043 cm-1 due to Cu--CO. Relaxation in the dark is rapid and quantitative at 210 K, but becomes negligible below 140 K. The multiple absorptions indicate structural heterogeneity of cytochrome oxidase in mitochondria. The Cu--CO absorptions (vCO) are similar to those in hemocyanin--CO complexes from molluscs (vCO - 2062 cm-1) and crustaceans (vCO = 2043 cm-1). The 2062 cm-1 Cu--CO absorption of cytochrome oxidase is split into two bands at 15 K. Analysis of spectral data suggest the presence of a very nonpolar heme--Cu pocket in which the heme-CO complex is highly ordered, but in which the Cu--CO complex is much more flexible, especially above 80 K. A function for these structures in oxygen reduction is proposed.
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- Erecińska M., Wilson D. F. Cytochrome c oxidase: a synopsis. Arch Biochem Biophys. 1978 May;188(1):1–14. doi: 10.1016/0003-9861(78)90348-x. [DOI] [PubMed] [Google Scholar]
- Fager L. Y., Alben J. O. Structure of the carbon monoxide binding site of hemocyanins studied by Fourier transform infrared spectroscopy. Biochemistry. 1972 Dec 5;11(25):4786–4792. doi: 10.1021/bi00775a023. [DOI] [PubMed] [Google Scholar]
- Holden C. For aging research the best is yet to be. Science. 1976 Jun 11;192(4244):1082–1082. doi: 10.1126/science.192.4244.1082. [DOI] [PubMed] [Google Scholar]
- Jung D. W., Chávez E., Brierley G. P. Energy-dependent exchange of K+ in heart mitochondria. K+ influx. Arch Biochem Biophys. 1977 Oct;183(2):452–459. doi: 10.1016/0003-9861(77)90380-0. [DOI] [PubMed] [Google Scholar]
- Lindsay J. G., Wilson D. F. Reaction of cytochrome C oxidase with CO: involvement of the invisible copper. FEBS Lett. 1974 Nov 1;48(1):45–49. doi: 10.1016/0014-5793(74)81058-6. [DOI] [PubMed] [Google Scholar]
- Schroedl N. A., Hartzell C. R. Oxidative titrations of reduced cytochrome aa3: influence of cytochrome c and carbon monoxide on the midpoint potential values. Biochemistry. 1977 Nov 15;16(23):4966–4971. doi: 10.1021/bi00642a004. [DOI] [PubMed] [Google Scholar]
- Sharrock M., Yonetani T. Low-temperature flash photolysis studies of cytochrome oxidase and its environment. Biochim Biophys Acta. 1977 Dec 23;462(3):718–730. doi: 10.1016/0005-2728(77)90113-x. [DOI] [PubMed] [Google Scholar]
- Sharrock M., Yonetani T. Study of cytochrome oxidase co-binding site using low-temperature flash photolysis. Biochim Biophys Acta. 1976 Jun 15;434(2):333–344. doi: 10.1016/0005-2795(76)90225-7. [DOI] [PubMed] [Google Scholar]
- Thomson A. J., Brittain T., Greenwood C., Springall J. P. Variable-temperature magnetic-circular-dichroism spectra of cytochrome c oxidase and its derivatives. Biochem J. 1977 Aug 1;165(2):327–336. doi: 10.1042/bj1650327. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Tweedle M. F., Wilson L. J. Electronic state of heme in cytochrome oxidase III. The magnetic susceptibility of beef heart cytochrome oxidase and some of its derivatives from 7-200 K. Direct evidence for an antiferromagnetically coupled Fe (III)/Cu (II) pair. J Biol Chem. 1978 Nov 25;253(22):8065–8071. [PubMed] [Google Scholar]
- Van Gelder B. F., Beinert H. Studies of the heme components of cytochrome c oxidase by EPR spectroscopy. Biochim Biophys Acta. 1969 Sep 16;189(1):1–24. doi: 10.1016/0005-2728(69)90219-9. [DOI] [PubMed] [Google Scholar]
- Volpe J. A., O'Toole M. C., Caughey W. S. Quantitative infrared spectroscopy of CO complexes of cytochrome c oxidase, hemoglobin and myoglobin: evidence for one CO per heme. Biochem Biophys Res Commun. 1975 Jan 6;62(1):48–53. doi: 10.1016/s0006-291x(75)80403-7. [DOI] [PubMed] [Google Scholar]
- Yoshikawa S., Choc M. G., O'Toole M. C., Caughey W. S. An infrared study of CO binding to heart cytochrome c oxidase and hemoglobin A. Implications re O2 reactions. J Biol Chem. 1977 Aug 10;252(15):5498–5508. [PubMed] [Google Scholar]