Protein-heme interactions in hemoglobin from the mollusc Scapharca inaequivalvis: evidence from resonance Raman scattering.

摘要: Resonance Raman spectra of the Scapharca inaequivalvis homodimeric hemoglobin (HbI) have been measured for ligand-bound and ligand-free ferrous forms protein. In deoxy derivative, iron-histidine (Fe-His) stretching mode, proposed as a marker oxygen affinity conduit linking hemes to subunit interface, gives rise peak centered at 203 cm-1, an unusually low frequency compared that reported other hemoglobins myoglobins. CO-bound three isotope-sensitive lines 517, 583, 1945 cm-1 assigned Fe-CO stretching, Fe-C-O bending, C-O modes, respectively. From frequencies these modes from their relative intensities, geometry appears be tilted axial coordination shows bending angle which has estimated about 171 +/- 5 degrees. For only one detected 570 in line with values found myoglobin hemoglobins. HbI modified p-(chloromercuri)benzoate (PMB) Cys92 parallel those native Despite large increase produced by PMB modification, Fe-His mode is unshifted derivative.(ABSTRACT TRUNCATED AT 250 WORDS)