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Resonance Raman studies of heme structural differences in subunits of deoxy hemoglobin
Author(s) -
Podstawka Edyta,
Rajani Cynthia,
Kincaid James R.,
Proniewicz Leonard M.
Publication year - 2000
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/1097-0282(2000)57:4<201::aid-bip1>3.0.co;2-7
Subject(s) - tetramer , chemistry , heme , protein subunit , raman spectroscopy , hemeprotein , hemoglobin , stereochemistry , crystallography , resonance (particle physics) , beta (programming language) , nuclear magnetic resonance , biochemistry , gene , enzyme , physics , programming language , particle physics , computer science , optics
Abstract Low frequency resonance Raman (RR) spectra are reported for deoxy hemoglobin (Hb), its isolated subunits, its analogue bearing methine‐deuterated hemes in all four subunits (Hb‐d 4 ), and the hybrids bearing the deuterated heme in only one type of subunit, which are [α d4 β h4 ] 2 and [α h4 β d4 ] 2 . Analyzed collectively, the spectra reveal subunit‐specific modes that conclusively document subtle differences in structure for the heme prosthetic groups in the two types of subunits within the intact tetramer. Not surprisingly, the most significant spectral differences are observed in the γ 7 mode that has a major contribution from out of plane bending of the methine carbons, a distortion that is believed to relieve strain in the high‐spin heme prosthetic groups. The results provide convincing evidence for the utility of selectively labeled hemoglobin hybrids in unraveling the separate subunit contributions to the RR spectra of Hb and its various derivatives and for thereby detecting slight structural differences in the subunits. © 2000 John Wiley & Sons, Inc. Biopolymers (Biospectroscopy) 57: 201–207, 2000