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Ultraviolet resonance Raman spectroscopy of X—Proline bonds: A new marker band of hydrogen bonding at the imide CO site
Author(s) -
Takeuchi Hideo,
Harada Issei
Publication year - 1990
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.1250210807
Subject(s) - hydrogen bond , imide , chemistry , raman spectroscopy , isomerization , resonance raman spectroscopy , photochemistry , resonance (particle physics) , crystallography , molecule , polymer chemistry , organic chemistry , catalysis , atomic physics , optics , physics
UV resonance Raman spectra of proline‐containing peptides were measured in order to study the effects of transcis isomerization and hydrogen bonding on the imide II [C(O)‐N stretch] vibration of the X‐Pro bond. The isomerization does not affect the imide II frequency noticeably but the hydrogen bonding at the CO site increases the frequency markedly, which varies from ca. 1445 cm −1 in the non‐hydrogen‐bonding state to ca. 1485 cm −1 in a strongly hydrogen‐bonded state (from 1440 to 1465 cm −1 for Pro‐Pro linkages). The large upward frequency shift on hydrogen bonding indicates that the imide II frequency can serve as a structural marker of X‐Pro bonds, particularly in distinguishing bent peptide backbones involving different hydrogen bonding states of the imide CO group. Applications of this marker band to structural studies of proline‐containing oligopeptides are demonstrated for tuftsin, bradykinin and gramicidin S.