FEBS Letters | |
Electron entry in a CuA mutant of cytochrome c oxidase from Paracoccus denitrificans. Conclusive evidence on the initial electron entry metal center | |
Malatesta, Francesco1  Zickermann, Volker2  Brunori, Maurizio1  Ludwig, Bernd2  Nicoletti, Flavia1  | |
[1] Department of Biochemical Sciences ‘A. Rossi Fanelli’ and CNR Centre of Molecular Biology, University of Rome ‘La Sapienza’, Piazzale Aldo Moro 5, 00185 Rome, Italy;Institute of Biochemistry, Molecular Genetics, University of Frankfurt, Biozentrum, Frankfurt, Germany | |
关键词: Cytochrome c oxidase; Electron transfer; Site-directed mutagenesis; | |
DOI : 10.1016/S0014-5793(98)01006-0 | |
学科分类:生物化学/生物物理 | |
来源: John Wiley & Sons Ltd. | |
【 摘 要 】
A cytochrome c oxidase subunit II C216S mutant from Paracoccus denitrificans in which the CuA site was changed by site-directed mutagenesis to a mononuclear copper site [Zickermann, V., Wittershagen, A., Kolbesen, B.O. and Ludwig, B. Biochemistry 36 (1997) 3232–3236] was investigated by stopped-flow spectroscopy. Contrary to the behavior of the wild type enzyme, in this mutant cytochrome a cannot be reduced by excess cytochrome c in the millisecond time scale in which cytochrome c oxidation is observed. The results conclusively identify and establish CuA as the initial electron entry site in cytochrome c oxidase. Partial rapid reduction (ca. 20%) of the modified CuA site suggests that the mononuclear copper ion has a redox potential ca. 100 mV lower than the wild type, and that internal electron transfer to cytochrome a is ≥103-fold slower than with the wild type enzyme.
【 授权许可】
Unknown
【 预 览 】
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