Protein dynamics of heme-heme oxygenase-1 complex following carbon monoxide dissociation

Structural changes of heme-heme oxygenase-1 complex following carbon monoxide (CO) dissociation were studied by time-resolved resonance Raman spectroscopy. We observed temporal changes for resonance Raman bands of the Fe-His stretch and the heme propionate bends in the subnanosecond and microsecond time regimes. These changes suggest structural rearrangements in the Fe-His linkage and the salt bridges of the heme propionates following CO dissociation. The present data supports the model proposed by an X-ray crystallographic study. The Fe-His stretching mode exhibited an upshift until 30 mu s after dissociation as the delay time increased. This is the first example of a CO-dissociation-induced strengthening of the Fe-His linkage in hemeproteins. Copyright (C) 2010 John Wiley & Sons, Ltd.