Biophysical Journal 50: 613-620 (1986)
© 1986 the Biophysical Society

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Argade, P V Articles by Rousseau, D L Search for Related Content PubMed PubMed Citation Articles by Argade, P V Articles by Rousseau, D L

Resonance Raman spectral isolation of the a and a3 chromophores in cytochrome oxidase.

ABSTRACT

Resonance Raman spectra of reduced CO-bound cytochrome oxidase obtained at two different excitation frequencies (441.6 and 413.1 nm) are compared with the spectra of the fully reduced enzyme. In the spectra of the CO-bound complex only the cytochrome a modes are strongly enhanced with 441.6 nm excitation and only the modes of the CO-bound cytochrome a3 heme are strongly enhanced with 413.1-nm excitation. In the fully reduced complex with both excitation frequencies, modes of both cytochrome a and a3 are enhanced. By subtraction we are able to uncover the complete spectrum of the fully reduced ligand-free cytochrome a3 heme. Thus, we report the discrete resonance Raman spectra of cytochromes a2+, a2+3, and a2+3 (CO). The spectra of fully reduced cytochrome a and ligand-free cytochrome a3 are very different especially in the low frequency region. Binding CO to ferrous cytochrome a3 results in electronic structure changes in the heme analogous to those in hemoglobin and myoglobin, from which we conclude that there is nothing electronically unique in the ferrous cytochrome a3 heme to account for its catalytic properties.

This article has been cited by other articles:

				S. Han, S. Takahashi, and D. L. Rousseau Time Dependence of the Catalytic Intermediates in Cytochrome c Oxidase J. Biol. Chem., January 21, 2000; 275(3): 1910 - 1919. [Abstract] [Full Text] [PDF]

				T. K. Das, C. M. Gomes, M. Teixeira, and D. L. Rousseau Redox-linked transient deprotonation at the binuclear site in the aa3-type quinol oxidase from Acidianus ambivalens: Implications for proton translocation PNAS, August 17, 1999; 96(17): 9591 - 9596. [Abstract] [Full Text] [PDF]