A comparative study of the resonance Raman spectra of bacterial cytochromes

Resonance Raman spectra were obtained for two newly isolated bacterial cytochromes, Alcaligenes faecalis (ATCC 8750) c554 and Alcaligenes faecalis c556. Their spectra were compared with those of mammalian cytochrome c and two other bacterial cytochromes, Paracoccus denitrificans c550 and Pseudomonas aeruginosa c551. The positions of the Raman bands indicated that, while Al. c554 and Al. c556 were c-type cytochromes with two thioether linkages, several common features found in their Raman spectra were anomalous. These features suggest that the electronic charge density of the porphyrin macrocycle of Al. c554 and Al. c556 is more asymmetric than that of other bacterial and mammalian c-type cytochromes. The Raman evidence indicates that the electronic properties of the heme are controlled by the protein in these two Alcaligenes cytochromes.