Comparison of the Effect of Five Guest Residues on the \beta-Sheet Conformation of Host ${(L-Val)}_n$ Oligopeptides

Moretto, V and Crisma, M and Bonora, GM and Toniolo, C and Balaram, Hemalatha and Balaram, P (1989) Comparison of the Effect of Five Guest Residues on the \beta-Sheet Conformation of Host ${(L-Val)}_n$ Oligopeptides. In: Macromolecules, 22 (7). pp. 2939-2944.

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Abstract

The synthesis, characterization, and IR absorption, 'H NMR, and CD properties of ${(L-Val)}_n$, host tetra-, penta-, and hexapeptides containing an L-Ile, L-Ala, D-Val, L-Pro, or Aib guest residue are reported, with the intention of establishing a scale of \beta-sheet disrupting capability of various amino acids. The results indicate that in the solid state the \beta-sheet structures of the ${(L-Val)}_n$, (n = 5,6) homopeptides are at least partially disrupted by the L-Pro and Aib residues. In ${CH}_2{Cl}_2$/${Me}_2SO$ solvent mixtures the following rank order is obtained for the stability of the \beta-sheets: L-Val> L-Val > L-Ile \gg L-Ala \gg D-Val > L-Pro \gg Aib. In $CD{Cl}_3$ solutions the Aib hexapeptide is folded into a partially labile $3_{10}$-helical structure. Statistically disordered conformations largely prevail in more polar solvents like 2,2,2-trifluoroethanol and ethanol in all the peptides examined. Only the ${(L-Val)}_n$, hexapeptide is prone to adopt the \beta-sheet conformation upon addition of 40% (v/v) water to the trifluoroethanol solution.

Item Type:	Journal Article
Additional Information:	Copyright for this article belongs to American Chemical Society.
Department/Centre:	Division of Biological Sciences > Molecular Biophysics Unit
Date Deposited:	15 Feb 2005
Last Modified:	19 Sep 2010 04:18
URI:	http://eprints.iisc.ernet.in/id/eprint/2785

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