Co-rebinding in myoglobin as seen by time-resolved X-ray absorption spectroscopy.
The dynamics of selected conformational coordinates, key roles in the understanding of the CO-rebinding process, are investigated in horse heart carbonmonoxy myoglobin (MbCO) through time-resolved X-ray absorption spectroscopy. We present here the results obtained at 90 K in the second time scale. The approach of the CO molecule towards the Fe atom in the active site pocket is speculated to act as a natural precursor to the Fe displacement with the consequent undoming of the protein porphyrin plane. The arrangement of the Fe-C-O bonding angle geometry follows and the final MbCO active site configuration is completely reached within 1 min.
Natali
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F
INFM, Operative Group in Grenoble CRG-IN13, ILL, 6 Avenue J. Horowitz, BP 156, 38042 Grenoble, France. natali@ill.fr
Schmithüsen
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F
D015502:Absorptiometry, Photon / Q000379:methods; D000818:Animals; D002248:Carbon Monoxide / Q000378:metabolism; D006736:Horses; D007700:Kinetics; D009206:Myocardium / Q000378:metabolism; D009211:Myoglobin / Q000737:chemistry* / Q000378:metabolism*; D011487:Protein Conformation; D013997:Time Factors
D009211:Myoglobin; C018013:carboxymyoglobin; D002248:Carbon Monoxide