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Conformational study on poly[γ‐(α‐phenethyl)‐ L ‐glutamate] using vibrational circular dichroism spectroscopy
Author(s) -
Tanaka Takeyuki,
Inoue Katsuhiko,
Kodama Takashi,
Kyogoku Yoshimasa,
Hayakawa Tadao,
Sugeta Hiromu
Publication year - 2001
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.1017
Subject(s) - chemistry , circular dichroism , chirality (physics) , vibrational circular dichroism , side chain , stereochemistry , amide , cotton effect , protein secondary structure , chloroform , spectroscopy , absorption (acoustics) , helix (gastropod) , crystallography , chiral symmetry , organic chemistry , polymer , physics , biochemistry , ecology , quantum mechanics , snail , nambu–jona lasinio model , biology , quark , acoustics
Vibrational circular dichroism (VCD) and IR absorption spectra are obtained in a chloroform solution for poly[γ‐((R)‐α‐phenethyl)‐ L ‐glutamate] (PRPLG) and poly[γ‐((S)‐α‐phenethyl)‐ L ‐glutamate] (PSPLG), whose only structural difference is an opposite chiral center in the side chain. Their characteristic amide A, I, and II bands show VCD patterns quite similar to those of poly[γ‐benzyl‐ L ‐glutamate] (PBLG), indicating that the secondary structure of these polypeptides is a right‐handed α‐helix. The VCD spectra in the CH stretching region exhibit different patterns for PRPLG and PSPLG, reflecting the chirality difference in the side chains. This difference is interpreted on the basis of the additivity of optical activity contributions from the main chain conformation and the chirality difference in the side chains. The results indicate that a VCD difference spectrum of the CH stretching region is a useful diagnostic tool for elucidating local chirality differences. © 2001 John Wiley & Sons, Inc. Biopolymers (Biospectroscopy) 62: 228–234, 2001