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Theoretical π‐π* absorption, circular dichroic, and linear dichroic spectra of collagen triple helices
Author(s) -
Caldwell James W.,
Applequist Jon
Publication year - 1984
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/bip.360231006
Subject(s) - dichroic glass , chemistry , spectral line , absorption spectroscopy , crystallography , absorption (acoustics) , dipole , circular dichroism , stereochemistry , materials science , optics , physics , nanotechnology , organic chemistry , astronomy
Absorption, CD, and LD spectra of the π‐π* transition near 200 nm are calculated for poly(Gly‐X‐Y) (X,Y = Gly, Ala, Pro) in four conformations proposed for collagen like triple helices in the recent literature. A dipole interaction model is used with the same optical paramenters as in previous studies of polypeptide spectra. The CD spectra are sensitive to backbone structure and amino acid composition, although the experimentally observed negative peak near 200 nm is a general feature of most the calculated spectra. Interchain interactions significantly affect the CD spectra in most cases. Calculations for (Gly‐Pro‐Ala) 3 and (Gly‐Ala‐Pro) 3 in the triple helical structure of Fraser, MacRae, and Suzuki [(1979) J. Mol. Biol. 129 , 463–481] show absorption, CD, and LD spectra in fairly good agreement with experiment. The characteristics of the π‐π* normal modes responsible for the calculated spectra are compared with those of the component bands resolved from the experimental spectra of collagen by Mandel and Holzwarth [(1973) Biopolymers 12 , 655–674].