Subpicosecond resonance Raman spectroscopy of carbonmonoxy- and oxyhemoglobin.
In this paper we present the resonance Raman spectrum of the carbonmonoxy- (HbCO) and oxyhemoglobin (HbO2) photointermediates on a 800-900 fs timescale. In the case of HbCO, the frequencies of the so-called core-size markers (1500-1650 cm-1) are characteristic of a deoxylike photoproduct in a high spin state (S = 2) with a partially domed heme. The spectrum of the HbO2 photointermediate, on the other hand, is different, and may be characteristic of an excited-state species. These results are discussed in terms of a reaction scheme previously presented by Petrich, J. W., C. Poyart, and J. L. Martin (1988. Biochemistry. 27:4049-4060) and compared with those obtained in the literature on a 30-40 ps timescale. In both molecules a distinct downshift of the v4 mode was observed with respect to the equilibrium value, which is indicative of an elevated temperature of the heme after photodissociation.
van den Berg
R
R
Department of Chemistry and Biochemistry, University of California, Los Angeles 90024.
el-Sayed
M A
MA
D055592:Biophysical Phenomena; D001703:Biophysics; D002263:Carboxyhemoglobin / Q000737:chemistry* / Q000528:radiation effects; D006801:Humans; D066298:In Vitro Techniques; D010108:Oxyhemoglobins / Q000737:chemistry / Q000528:radiation effects; D010777:Photochemistry; D013059:Spectrum Analysis, Raman
D010108:Oxyhemoglobins; D002263:Carboxyhemoglobin