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The optical activity of polypeptides
Author(s) -
Schellman John A.,
Becktel Wayne J.
Publication year - 1983
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.360220127
Subject(s) - chemistry , anisotropy , perpendicular , polyproline helix , linear dichroism , exciton , dichroism , optical anisotropy , interpretation (philosophy) , circular dichroism , crystallography , chemical physics , cotton effect , condensed matter physics , optics , physics , geometry , peptide , biochemistry , mathematics , programming language , computer science
The present status of the theory of the optical properties of polypeptides is discussed in a general way. Arguments are presented that indicate that the interaction of exciton bands in helices will occur in a tensorial way with the parallel polarized bands normally having stronger interactions than the perpendicular polarized bands, with only small cross‐interactions. The net result is an anisotropy of the hyperchromism of the ππ* band and an imbalance of the rotatory strengths of the parallel and perpendicular components. According to the evidence of Mandel and Holzwarth [(1973) Biopolymers 13 , 655–674], this is, in fact, the origin of the strongly nonconservative CD bands of polyproline II and related structures. The implications of anisotropic hyperchromicity on the interpretation of the linear dichroism of crystals is discussed.