Time-resolved resonance Raman study of recombination intermediates of photodissociated CO of myoglobin and its E7 mutants

摘要

Recombination intermediates of photodissociated CO of horse and human MbCO were investigated by using pump/probe time-resolved resonance Raman technique with 10 ns resolution. It became evident that the species with the $nu$-Fe-CO$/ around 490 cm$+$MIN@1$/ recombines CO much faster than that with $nu$-Fe-CO$/ around 510 cm$+$MIN@1$/, and that the 490 cm$+$MIN@1$/ species is not a precursor of the 510 cm$+$MIN@1$/ species, although the former and latter have been assumed to reflect the 'open' and 'closed' forms for the ligand entry. The faster recovery of the 490 cm$+$MIN@1$/ species is attributed to the increased contribution of the recombination from the protein separated pair due to stabilization of CO under more hydrophobic protein environments.