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A demonstration of two‐component behaviour of the circular dichroic spectra of poly( L ‐tyrosine, 3‐bromo‐ L ‐tyrosine) in trimethylphosphate
Author(s) -
Applequist Jon,
Lunde Barbara K.
Publication year - 1974
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.1974.360130705
Subject(s) - dichroic glass , chemistry , tyrosine , side chain , circular dichroism , spectral line , helix (gastropod) , stereochemistry , component (thermodynamics) , crystallography , polymer , biochemistry , organic chemistry , physics , optics , ecology , thermodynamics , astronomy , snail , biology
The circular dichroic spectrum of poly(Tyr,TyrBr) in trimethylphosphate from 180 to 320 nm is found to be a linear function of composition from 25 to 68% TyrBr, and the spectra of the Tyr and TyrBr components are resolved. For Tyr the resolved spectrum is in agreement with available CD spectra of poly(Tyr). These results are interpreted to mean that the side‐chain conformations of Tyr and TyrBr are not affected by the other component, and that for Tyr the conformation is the same as in poly(Tyr). It is also concluded that poly(Tyr,TyrBr) is helical with the same helix sense as poly(Tyr). The restrictions on the side‐chain conformations are discussed, and it is suggested that the Tyr and TyrBr side chains are all in the same χ 1 region.