Ultrafast Dynamics of Carboxy-Hemoglobin: Two-Dimensional Infrared Spectroscopy Experiments and Simulations.
This Letter presents a comparison between experimental and simulated 2D mid-infrared spectra of carboxy-hemoglobin in the spectral region of the carbon monoxide stretching mode. The simulations rely on a fluctuating potential energy surface that includes both the effect of heme and the protein surroundings computed from molecular dynamics simulations. A very good agreement between theory and experiment is obtained with no adjustable parameters. The simulations show that the effect of the distal histidine through the hydrogen bond is strong and is directly responsible for the slow decay of the frequency-frequency correlation function on a 10 ps time scale. This study confirms that fluctuations in carboxy-hemoglobin are more inhomogeneous than those in the more frequently studied carboxy-myoglobin. The comparison between simulations and experiments brings valuable information on the complex relation between protein structure and spectral diffusion.
†Institut des Sciences Moléculaires d'Orsay, Univ Paris-Sud, CNRS UMR 8214, 91405 Orsay, France.
Cyril
C
Falvo
‡Laboratoire d'Optique et Biosciences, Ecole Polytechnique, CNRS UMR 7645, INSERM U1182, 91128 Palaiseau, France.
Louis
L
Daniault
‡Laboratoire d'Optique et Biosciences, Ecole Polytechnique, CNRS UMR 7645, INSERM U1182, 91128 Palaiseau, France.
Thibault
T
Vieille
‡Laboratoire d'Optique et Biosciences, Ecole Polytechnique, CNRS UMR 7645, INSERM U1182, 91128 Palaiseau, France.
Vincent
V
Kemlin
‡Laboratoire d'Optique et Biosciences, Ecole Polytechnique, CNRS UMR 7645, INSERM U1182, 91128 Palaiseau, France.
Jean-Christophe
JC
Lambry
§Laboratoire Collisions Agrégats et Réactivité, IRSAMC, Université Paul Sabatier, CNRS UMR 5589, 31062 Toulouse, France.
Christoph
C
Meier
‡Laboratoire d'Optique et Biosciences, Ecole Polytechnique, CNRS UMR 7645, INSERM U1182, 91128 Palaiseau, France.
Marten H
MH
Vos
‡Laboratoire d'Optique et Biosciences, Ecole Polytechnique, CNRS UMR 7645, INSERM U1182, 91128 Palaiseau, France.
Adeline
A
Bonvalet
‡Laboratoire d'Optique et Biosciences, Ecole Polytechnique, CNRS UMR 7645, INSERM U1182, 91128 Palaiseau, France.
Manuel
M
Joffre
D017666:Deuterium Oxide / Q000737:chemistry; D004058:Diffusion; D006801:Humans; D056004:Molecular Dynamics Simulation; D009211:Myoglobin / Q000737:chemistry* / Q000378:metabolism; D013055:Spectrophotometry, Infrared
D009211:Myoglobin; C018013:carboxymyoglobin; D017666:Deuterium Oxide
2D-IR; carboxy-hemoglobin; protein dynamics; ultrafast dynamics