Folding propensity and biological activity of peptides: the effect of a single stereochemical isomerization on the conformational properties of bombinins in aqueous solution.

Full Abstract

Folding propensities of bombinins H2 and H4, two members of amphibian bombinins H, a family of 17-20 residue alpha-helical peptides, have been investigated by means of circular dichroism (CD) measurements and molecular dynamics (MD) simulations. The two peptides, with primary structure IIGPVLGLVGSALGGLLKKI-NH2 and differing only for the configuration of the second aminoacid (an L-isoleucine in H2 and a D-alloisoleucine in H4) behave rather differently in solution. In particular both CD measurements and MD simulations indicate that bombinin H2 shows a markedly higher tendency to fold. From a careful inspection of MD trajectories it emerges that the stereochemical isomerization mutation of residue 2 to D-alloisoleucine in H4 peptide, drastically decreases its ability to form intrapeptide contacts. MD simulations also indicate that the conformational sampling in both systems derives from a subtle combination of energetic and entropic effects both involving the peptide itself and the solvent. The present results have been finally paralleled with preliminary information on bombinins H2 and H4 biological activity, i.e. interaction with membrane, supporting the hypothesis of an "already folded" conformation in water rather than interfacial folding tenet.

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Author information

Author/s: Bozzi, Argante (A); Mangoni, Maria Luisa (ML); Rinaldi, Andrea C (AC); Mignogna, Giuseppina (G); Aschi, Massimiliano (M);

Affiliation: Dipartimento di Scienze e Tecnologie Biomediche, Università L'Aquila e Consorzlo INBB, Italy.

Journal and publication information

Publication Type: Journal Article; Research Support, Non-U.S. Gov't

Journal: Biopolymers (Biopolymers), published in United States. (Language: eng)

Reference: 2008-Sep; vol 89 (issue 9) : pp 769-78

Dates: Created 2008/06/24; Completed 2008/08/19;

PMID: 18459169, status: MEDLINE (last retrieval date: 11/6/2008)

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MeSH headings (categories)

This article was linked to the MESH Headings shown below.

Amphibian Proteins - chemistry
Antimicrobial Cationic Peptides - chemistry
Cell Membrane - chemistry
Circular Dichroism

Associated Chemicals: Amphibian Proteins (0) ; Antimicrobial Cationic Peptides (0) ; bombinin H2 (0)

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