Evidence for heme-heme excitonic coupling in the Soret circular dichroism of hemoglobin.
Biochem Biophys Res Commun
; 235(3): 610-4, 1997 Jun 27.
Article
in En
| MEDLINE
| ID: mdl-9207206
ABSTRACT
In order to study interdimer heme-heme electronic interactions in human hemoglobin, the Soret circular dichroism spectrum of the carboxy adduct is measured as a function of protein concentration, the spectrum at the highest concentration representing primarily that of alpha2beta2 tetramers (93%) and the lowest concentration representing primarily alphabeta dimers (68%). The tetramer-dimer difference spectrum, obtained using singular value decomposition and linear least squares fitting from a matrix of CD spectra measured at ten concentrations, is roughly conservative, with a larger negative lobe at shorter wavelengths and a peak-to-trough magnitude that is 18% of the tetramer's maximum Soret CD magnitude. It is tentatively assigned to heme-heme excitonic interactions on the basis of theoretical predictions by R. W. Woody [(1985) in Optical Properties and Structure of Tetrapyrroles (Blauer, G., and Sund, H., Eds.), pp. 239-256, Walter de Gruyter, New York].
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Protein Conformation
/
Hemoglobins
/
Heme
Limits:
Humans
Language:
En
Journal:
Biochem Biophys Res Commun
Year:
1997
Document type:
Article
Affiliation country:
United States