Structural studies of model peptides \beta-, \gamma- containing and \delta- amino acids

Sengupta, Anindita and Aravinda, Subrayashastry and Shamala, Narayanaswamy and Raja, Muruga Poopathi K and Balaram, Padmanabhan (2006) Structural studies of model peptides \beta-, \gamma- containing and \delta- amino acids. In: Organic and Biomolecular Chemistry, 4 (22). pp. 4214-4222.

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Abstract

The crystal structures of five model peptides Piv-Pro-Gly-NHMe (1), Piv-Pro-\beta Gly-NHMe (2), Piv-Pro- \beta Gly-OMe (3), Piv-Pro- \delta Ava-OMe (4) and Boc-Pro- \gamma Abu-OH (5) are described (Piv: pivaloyl; NHMe: N-methylamide; \beta Gly: \beta-glycine; OMe: O-methyl ester; \delta Ava: \delta -aminovaleric acid; \gamma Abu: \gamma -aminobutyric acid). A comparison of the structures of peptides 1 and 2 illustrates the dramatic consequences upon backbone homologation in short sequences. 1 adopts a type II \beta -turn conformation in the solid state, while in 2, the molecule adopts an open conformation with the \beta -residue being fully extended. Piv-Pro- \beta Gly-OMe (3), which differs from 2 by replacement of the C-terminal NH group by an O-atom, adopts an almost identical molecular conformation and packing arrangement in the solid state. In peptide 4, the observed conformation resembles that determined for 2 and 3, with the \delta Ava residue being fully extended. In peptide 5, the molecule undergoes a chain reversal, revealing a \beta -turn mimetic structure stabilized by a $C-H...O$ hydrogen bond.

Item Type:	Journal Article
Publication:	Organic and Biomolecular Chemistry
Publisher:	Royal Society of Chemistry
Additional Information:	Copyright of this article belongs to Royal Society of Chemistry.
Department/Centre:	Division of Biological Sciences > Molecular Biophysics Unit Division of Physical & Mathematical Sciences > Physics
Date Deposited:	03 Jun 2008
Last Modified:	19 Sep 2010 04:45
URI:	http://eprints.iisc.ac.in/id/eprint/14093

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