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Context-dependent conformation of diethylglycine residues in peptides

Kaul, R and Balaram, P and Banumathi, S and Velmurugan, D and Ravikumar, K and Rao, Balaji R (2000) Context-dependent conformation of diethylglycine residues in peptides. In: Journal of Peptide Research, 55 (4). pp. 271-278.

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Abstract

Diethylglycine (Deg) residues incorporated into peptides can stabilize fully extended $(C_5)$ or helical conformations. The conformations of three tetrapeptides Boc-Xxx-Deg-Xxx-Deg-OMe (Xxx = Gly, GD4; Leu, LD4 and Pro, PD4) have been investigated by NMR. In the Gly and Leu peptides, NOE data suggest that the local conformations at the Deg residues are fully extended. Low temperature coefficients for the Deg(2) and Deg(4) NH groups are consistent with their inaccessibility to solvent, in a $C_5$ conformation. NMR evidence supports a folded \beta-turn conformation involving Deg(2)-Gly(3), stabilized by a 4 \rightarrow1 intramolecular hydrogen bond between Pro(1) CO and Deg(4) NH in the proline containing peptide (PD4). The crystal structure of GD4 reveals a hydrated multiple turn conformation with Gly(1)–Deg(2) adopting a distorted type II/II conformation, while the Deg(2)–Pro(3) segment adopts a type III/III structure. A lone water molecule is inserted into the potential 4 \rightarrow1 hydrogen bond of the Gly(1)–Deg(2) \beta-turn.

Item Type: Journal Article
Additional Information: Copyright of this article belongs to John Wiley & Sons.
Keywords: diethylglycine residues;extended C5 conformations;NMR of peptides;peptide conformation;peptide crystal structure.
Department/Centre: Division of Biological Sciences > Molecular Biophysics Unit
Date Deposited: 25 Aug 2008
Last Modified: 19 Sep 2010 04:49
URI: http://eprints.iisc.ernet.in/id/eprint/15608

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