Coexistence of Folded and Extended Conformations of a Tripeptide Containing alpha,alpha-Di-n-propylglycine in Crystals

Prasad, S and Mitra, S and Subramanian, E and Velmurugan, D and Rao, RB and Balaram, P (1994) Coexistence of Folded and Extended Conformations of a Tripeptide Containing alpha,alpha-Di-n-propylglycine in Crystals. In: Biochemical and Biophysical Research Communications, 198 (2). pp. 424-430.

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Abstract

The crystal structure of the tripeptide Boc-Leu-Dpg-Val-OMe (Dpg, alpha, alpha-di-n-propylglycine) reveals the coexistence of two distinct backbone conformations. In molecule A the Dpg residue adopts a fully extended conformation (phi = 76.0°, psi=180.0°) while in molecule B a left handed helical conformation (phi = 62.8°, psi= 39.6°) is observed. Molecule B adopts a folded structure corresponding to a highly distorted Type II beta-turn conformation, which lacks an intramolecular 4 → 1 hydrogen bond. In contrast, molecule A has an open, extended conformation. The results demonstrate that both fully extended and helical conformations are energetically accessible to the Dpg residue.

Item Type:	Journal Article
Publication:	Biochemical and Biophysical Research Communications
Publisher:	Academic Press
Additional Information:	Copyright for this article belongs to Academic Press.
Department/Centre:	Division of Biological Sciences > Molecular Biophysics Unit
Date Deposited:	11 Nov 2004
Last Modified:	17 Jan 2012 09:57
URI:	http://eprints.iisc.ac.in/id/eprint/2317

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