title: Differences between protein dynamics of hemoglobin upon dissociation of oxygen and carbon monoxide.
abstract: Protein dynamics of human adult hemoglobin (HbA) upon ligand photolysis of oxygen (O(2)) and carbon monoxide (CO) was investigated using time-resolved resonance Raman (TR(3)) spectroscopy. The TR(3) spectra of the both photoproducts at 1-ns delay differed from that of the equilibrium deligated form (deoxy form) in the frequencies of the iron-histidine stretching [ν(Fe-His)] and methine wagging (γ(7)) modes, and the band intensity of pyrrole stretching and substituent bending (ν(8)) modes. Spectral changes of the O(2) photoproduct in the submicrosecond region were faster than those of the CO photoproduct, indicating that the structural dynamics following the photodissociation is ligand dependent for HbA. In contrast, no ligand dependence of the dynamics was observed for myoglobin, which has a structure similar to that of the subunit of HbA. The structural dynamics and relevance to the functionality of HbA also are discussed.
authors.affiliation: Graduate School of Science and Technology, Kobe University, Nada, Kobe 657-8501, Japan.
authors.forename: Yuka
authors.initials: Y
authors.lastname: Murakawa
authors.forename: Masako
authors.initials: M
authors.lastname: Nagai
authors.forename: Yasuhisa
authors.initials: Y
authors.lastname: Mizutani
mesh_terms: D000328:Adult; D002248:Carbon Monoxide / Q000378:metabolism*; D006441:Hemoglobin A / Q000378:metabolism*; D006801:Humans; D008958:Models, Molecular; D010100:Oxygen / Q000378:metabolism*; D011485:Protein Binding; D013059:Spectrum Analysis, Raman
chemical_list: D002248:Carbon Monoxide; D006441:Hemoglobin A; D010100:Oxygen