TY - JOUR
T1 - Resonance Raman spectra of cytochrome c oxidase. Excitation in the 600-nm region
AU - Bocian, David F.
AU - Lemley, Ann T.
AU - Petersen, Nils O.
AU - Brudvig, Gary W.
AU - Chan, Sunney I.
PY - 1979
Y1 - 1979
N2 - The resonance Raman (RR) spectra of oxidized, reduced, and oxidized cyanide-bound cytochrome c oxidase with excitation at several wavelengths in the 600-nm region are presented. No evidence is found for laser-induced photoreduction of the oxidized protein with irradiation at λ ∼600 nm at 195 K, in contrast to the predominance of this process upon irradiation in the Soret region at this temperature. The Raman spectra of all three protein species are very similar, and there are no Raman bands which are readily assignable to either cytochrome a or cytochrome a3, exclusively. The Raman spectra of the three protein species do, however, exhibit a number of bands not observed in the RR spectra of other hemoproteins upon excitation in their visible absorption bands. In particular, strong Raman bands are observed in the lowfrequency region of the RR spectra (-1)- The frequencies of these bands are similar to those of the copper-ligand vibrations observed in the RR spectra of type 1 copper proteins upon excitation in the 600-nm absorption band characteristic of these proteins. In cytochrome c oxidase, these bands do not disappear upon reduction of the protein and, therefore, cannot be attributed to copper-ligand vibrations. Thus, all the observed RR bands are associated with the two heme A moieties in the enzyme.
AB - The resonance Raman (RR) spectra of oxidized, reduced, and oxidized cyanide-bound cytochrome c oxidase with excitation at several wavelengths in the 600-nm region are presented. No evidence is found for laser-induced photoreduction of the oxidized protein with irradiation at λ ∼600 nm at 195 K, in contrast to the predominance of this process upon irradiation in the Soret region at this temperature. The Raman spectra of all three protein species are very similar, and there are no Raman bands which are readily assignable to either cytochrome a or cytochrome a3, exclusively. The Raman spectra of the three protein species do, however, exhibit a number of bands not observed in the RR spectra of other hemoproteins upon excitation in their visible absorption bands. In particular, strong Raman bands are observed in the lowfrequency region of the RR spectra (-1)- The frequencies of these bands are similar to those of the copper-ligand vibrations observed in the RR spectra of type 1 copper proteins upon excitation in the 600-nm absorption band characteristic of these proteins. In cytochrome c oxidase, these bands do not disappear upon reduction of the protein and, therefore, cannot be attributed to copper-ligand vibrations. Thus, all the observed RR bands are associated with the two heme A moieties in the enzyme.
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M3 - Article
C2 - 226125
AN - SCOPUS:0018780202
VL - 18
SP - 4396
EP - 4402
JO - Biochemistry
JF - Biochemistry
SN - 0006-2960
IS - 20
ER -