An infrared spectroscopic study of C7 intramolecular hydrogen bonds in peptides

Pulla Rao, Ch and Balaram, Padmanabhan and Rao, CNR (1983) An infrared spectroscopic study of C7 intramolecular hydrogen bonds in peptides. In: Biopolymers, 22 (9). pp. 2091-2104.

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Abstract

The ir-spectra in the N-H stretching region of Piv-Pro-NHMe and Boc-Pro-NHMe have been studied in carbon tetrachloride and chloroform solutions over a wide range of concentrations. Based on the concentration dependence of the N-H stretching bands, it has been shown that the characteristic N-H stretching band due to the C7 intramolecular hydrogen bond is around 3335 cm-'. Intermolecular hydrogen bonding also occurs to a small extent in these peptides, giving rise to a slight concentration dependence of the N-H stretching bands. The band around 3335 cm-* need not necessarily be due to C7 hydrogen bonds alone as proposed by Tsuboi et al. or to intermolecular hydrogen bonding alone as proposed by Maxfield et al.; this conclusion is supported by studies on Boc-Leu-NHMe, which undergoes only intermolecular hydrogen bonding We have shown that 2-Aib-Aib-OMe and Z-Aib- Ala-OMe form C7 intramolecular hydrogen bonds in addition to C5 intramolecular hydrogen bonds. The present studies also show that all the peptides studied exist in more than one conformation in solution.

Item Type:	Journal Article
Publication:	Biopolymers
Publisher:	John Wiley & Sons
Additional Information:	Copyright of this article belongs to John Wiley & Sons.
Department/Centre:	Division of Biological Sciences > Molecular Biophysics Unit
Date Deposited:	29 Oct 2010 05:43
Last Modified:	29 Oct 2010 05:43
URI:	http://eprints.iisc.ac.in/id/eprint/33471

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