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IR investigation on dehydrophenylalanine containing model peptides in helical conformation deposited on a crystal surface
Author(s) -
Gupta A.,
Mehrotra R.,
Tewari J.,
Jain R. M.,
Chauhan V. S.
Publication year - 1999
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/(sici)1097-0282(199911)50:6<595::aid-bip4>3.0.co;2-b
Subject(s) - chemistry , protein secondary structure , peptide , crystallography , infrared spectroscopy , crystal structure , spectral line , peptide conformation , amide , spectroscopy , crystal (programming language) , analytical chemistry (journal) , organic chemistry , physics , biochemistry , quantum mechanics , astronomy , computer science , programming language
Fourier transform ir spectra have been recorded for three 3 10 ‐helical and one α‐helical pentapeptides containing dehydrophenylalanine, in a thin solid film, in order to find marker bands for various secondary structures encountered in peptides containing dehydroaminoacids. The peptide solutions were deposited and dried as thin film on zinc selenide crystal surface. This convenient sampling method has provided reliable estimates of peptide secondary structure in solid state. Detailed vibrational assignments in the spectral region between 1200–1700 cm −1 are reported. In this region, peptide amide I, II, and III vibrations occur. Spectra–structure correlation has been presented based on the amide modes. Comparison of the ir spectra with available crystal structure data provides qualitative support for assignments of ir bands to 3 10 ‐helical structure and α‐helical structure in dehydrophenylalanine containing pentapeptides. Band frequency assignments for 3 10 ‐helical conformation are consistent for all three peptides. All the assignments agree closely with the theoretical predictions. The spectral differences between 3 10 ‐helical peptides and the α‐helical peptide have been highlighted. These findings demonstrate that a method based on ir spectroscopy can be developed for a useful approximation of three‐dimensional structure of dehydropeptides in solid state. © 1999 John Wiley & Sons, Inc. Biopoly 50: 595–601, 1999