VIBRATIONAL CIRCULAR DICHROISM STUDIES OF DEHYDROPHENYL ALANINE PEPTIDES
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Date
1990
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Publisher
Ohio State University
Abstract
The solution conformations of three peptides containing dehydrophenyl alanine ($\Delta^{Z}-Phe$) have been determined from their NH-, CH- and $C = O$. stretching vibrational circular dichroism spectra. We have found that the peptides $Ac-\Delta^{Z}-Phe-L-Ala-OMe (1), Ac-\Delta^{Z}-Phe-\Delta^{Z}-Phe-L-Ala-OMe (2)$. and $Boc-L-Ala-\Delta^{Z}-Phe-Gly-\Delta^{Z}-Phe-L-Ala-OMe (3)$ are all stabilized in chloroform solution by intramolecular hydrogen bonds. The conformation of the $C_{10}$-ring in peptide 1 and C10-ring (type I $\beta$-turn) in peptide 2 involving the $\Delta^{Z}-Phe$ residues is determined by the formation of a $C_{5}$-ring in the terminal L-Ala residue. Peptide 3 assumes several intramolecularly hydrogen-bonded conformations including a type III $\beta$-turn
Description
Author Institution: Department of Chemistry, Syracuse University; Instituto di Biofisica, Syracuse University