Evidence for sub-picosecond heme doming in hemoglobin and myoglobin: a time-resolved resonance Raman comparison of carbonmonoxy and deoxy species

A comparative study of the time-resolved resonance Raman signals from (carbonmonoxy)hemoglobin, deoxymyoglobin, (carbonmonoxy)myoglobin and deoxymyoglobin reveals that the completion of heme doming occurs very fast, on the sub-picosecond time scale. Heme doming is the major event leading to transduction of the bond breaking message into protein structural changes. Spectra data reveal the occurrence of ultrafast proximal histidine and tertiary F-helix displacement. Conformational changes generating cooperative R to T transition involve heme doming as a major event.