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Heme–heme interactions in tetramers and dimers of hemoglobin subunits: DeVoe theory calculations
Author(s) -
Woody Robert W.
Publication year - 2005
Publication title -
chirality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.43
H-Index - 77
eISSN - 1520-636X
pISSN - 0899-0042
DOI - 10.1002/chir.20192
Subject(s) - chemistry , heme , hemoglobin , hemeprotein , stereochemistry , biochemistry , enzyme
Detectable exciton couplets arising from heme–heme interactions in the hemoglobin (Hb) tetramers of HbO 2 and deoxyHb were predicted by DeVoe theory (Woody, in: Optical properties and structure of tetrapyrroles. Berlin: Walter deGruyter & Co.; 1985. p 239–259). This prediction was supported by the observation of an exciton couplet in the CD difference spectrum between the Hb tetramer and the αβ dimer of HbCO (Goldbeck et al., Biochem Biophys Res Commun 1997;235:610–614). In this paper, DeVoe theory is used to calculate the heme–heme interactions in the CO complex of the Hb tetramer (α 2 β 2 ) and dimer (αβ), the systems studied by Goldbeck et al. The couplet strength of the resulting theoretical CD difference spectrum agrees well with experiment, thus confirming that heme–heme interactions contribute significantly to the CD of HbCO. Given that the heme–heme distances in HbCO are 25 Å and more, it is highly likely that heme–heme interactions also contribute significantly to the CD of other multi‐heme proteins, e.g., cytochrome c 3 , cytochrome oxidase, cytochrome bc 1 , etc., where the hemes are in closer proximity. © 2005 Wiley‐Liss, Inc. Chirality 17:450–455, 2005.