Conformations of dehydrophenylalanine containing peptides: nmr studies of an acyclic hexapeptide with two Δz-Phe residues
Article first published online: 1 FEB 2004
Copyright © 1989 John Wiley & Sons, Inc.
Volume 28, Issue 3, pages 763–771, March 1989
How to Cite
Chauhan, V. S., Uma, K., Kaur, P. and Balaram, P. (1989), Conformations of dehydrophenylalanine containing peptides: nmr studies of an acyclic hexapeptide with two Δz-Phe residues. Biopolymers, 28: 763–771. doi: 10.1002/bip.360280306
- Issue published online: 1 FEB 2004
- Article first published online: 1 FEB 2004
- Manuscript Accepted: 20 JUL 1988
- Manuscript Received: 3 FEB 1988
The conformation of an acyclic dehydrophenylalanine (Δz-Phe) containing hexapeptide, Boc-Phe-Δz-Phe-Val-Phe-Δz-Phe-Val-OMe, has been investigated in CDCl3 and (CD3)2SO by 270-MHz 1H-nmr. Studies of NH group solvent accessibility and observation of interresidue nuclear Overhauser effects (NOEs) suggest a significant solvent-dependent conformational variability. In CDCl3, a population of folded helical conformations is supported by the inaccessibility to solvent of the NH groups of residues 3–6 and the detection of several NiH ⟷ Ni+1H NOEs. Evidence is also obtained for conformational heterogeneity from the detection of some CH ⟷ Ni+1H NOEs characteristic of extended strands. In (CD3)2SO, the peptide largely favors an extended conformation, characterized by five solvent-exposed NH groups and successive CH ⟷ Ni+1 H NOEs for the L-residues and CH ⟷ Ni+1H NOEs for the Δz-Phe residues. The results suggest that Δz-Phe residues do not provide compelling conformational constraints.