Time-resolved resonance raman spectroscopy of hemoglobin derivatives: heme structure changes in 7 nanoseconds.

Resonance Raman spectra of oxyhemoglobin, deoxyhemoglobin, carboxyhemoglobin, and the corresponding myoglobin derivatives have been obtained with 7-nanosecond laser pulses at 531.8 nanometers. The results suggest that no transient constraint of the heme group by the globin structure occurs on this time scale, and thus establish a temporal sequence for the early events that may participate in the stereochemical trigger mechanism of hemoglobin cooperativity.