Insertion of Methylene Units into the Turn Segment of Designed beta-Hairpin Peptides

Shankaramma, SC and Singh, Kumar S and Sathyamurthy, Aruna and Balaram, P (1999) Insertion of Methylene Units into the Turn Segment of Designed beta-Hairpin Peptides. In: Journal of the American Chemical Society, 121 (23). pp. 5360-5363.

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Abstract

The effect of insertion of methylene groups into the turn segment of beta-hairpin peptides has been investigated in the model sequence Boc-Leu-Val-Val-Dpro-delta-Ava-Leu-Val-Val-OMe. This sequence is related to the previously well-characterized model beta-hairpin octapeptide, Boc-Leu-Val-Val-DPro-Gly-Leu-Val-Val-OMe. Replacement of Gly by delta-Ava (delta-aminovaleric acid) formally corresponds to expansion of the turn segment from a two-residue loop to a three-residue loop. Backbone proton chemical shifts, vicinal coupling constants, and circular dichroism spectra for the two peptides are virtually indistinguishable. Nuclear Overhauser effects corresponding to short cross-strand interproton distances confirm that the registry of the beta-hairpin structure is maintained in the delta-Ava peptide. Restrained molecular dynamics simulations, using experimental constraints, yield two structural families that are consistent with the NOE data. Both families correspond to beta-hairpin conformations and differ only in the backbone torsion angles at the delta-Ava residue.

Item Type:	Journal Article
Publication:	Journal of the American Chemical Society
Publisher:	American Chemical Society
Additional Information:	Copyright for this article belongs to American Chemical Society.
Department/Centre:	Division of Biological Sciences > Molecular Biophysics Unit
Date Deposited:	04 Oct 2004
Last Modified:	19 Sep 2010 04:16
URI:	http://eprints.iisc.ac.in/id/eprint/2083

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