Resonance Raman spectra have been obtained for Spinacea oleracea, Phytolacca americana and Halobacterium halobium ferrodoxins. These spectra were very similar to each other in terms of both vibrational frequencies and relative intensities, strongly suggesting that their molecular structures of active centers are very similar. The resonance Raman spectra were, however, fairly different in the frequencies of Fe—S(Cys) stretching modes from the spectrum of beef adrenodoxin previously reported. Probably the nature of Fe—S(Cys)-bonding and/or the manner of cysteine ligation is somewhat different between adrenodoxin and the other [2Fe—2S] ferrodoxins.
