[Interpretation of the resonance Raman spectrum of cytochrome P-450]

Normal coordinate analysis has been carried out for the Fe(III) protoporphyrin IX dimethyl ester molecule and its vinyl deuterated analogs. All atoms of substituents were included explicitly in the calculations. On the basis of the calculation results the assignment of the resonance Raman active modes of cytochrome P-450 is given. Attention is mainly devoted to the assignment of vinyl and methyl propionate ester modes. It is shown that methyl propionate ester coordinates take part to a certain extent in the number of modes with frequencies below 1300 cm-1. The frequencies have been found which depend on the angle between the vinyl and macrocycle planes. In passing from perpendicular to in-plane conformation the theoretical frequencies of the delta (Cb C alpha C beta and delta (CCb C alpha) modes shift down by 70 and 220 cm-1 and the value of the last one is only about 110 cm-1.