Abstract
The pump/probe time-resolved resonance Raman (TR3) spectroscopy can detect a protein structural change in nsec resolution. The technique with 532nm pump and 416nm probe pulses was applied to observe a temporal change of the Fe-CO stretching vibration of MbCO which might take place during relaxation from 'open' to 'closed' forms upon CO binding. The UV TR3 experiment with 419nm pump and 217.8nm probe pulses revealed that β 37-Trp of HbCO was altered at 10-20 μs following photolysis, suggesting a likely mechanism of the quaternary structure transition upon CO dissociation.
