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Conformations of dehydrophenylalanine containing peptides: nmr studies of an acyclic hexapeptide with two z-Phe residues

Chauhan, VS and Uma, K and Kaur, Paramjeet and Balaram, P (1989) Conformations of dehydrophenylalanine containing peptides: nmr studies of an acyclic hexapeptide with two z-Phe residues. In: Biopolymers, 28 (3). pp. 763-771.

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Abstract

The conformation of an acyclic dehydrophenylalanine ( z-Phe) containing hexapeptide, Boc-Phe- z-Phe-Val-Phe- z-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 C[stack i ]H 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 C[stack i ]H Ni+1 H NOEs for the L-residues and C[stack i ]H Ni+1H NOEs for the z-Phe residues. The results suggest that z-Phe residues do not provide compelling conformational constraints.

Item Type: Journal Article
Additional Information: Copyright of this article belongs to John Wiley & Sons, Inc.
Keywords: dehydrophenylalanine;peptides;conformational variability;conformational constraints
Department/Centre: Division of Biological Sciences > Molecular Biophysics Unit
Date Deposited: 04 Jun 2004
Last Modified: 19 Sep 2010 04:12
URI: http://eprints.iisc.ernet.in/id/eprint/351

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