Generation and characterization of the antibacterial activity of a novel hybrid antimicrobial peptide comprising functional domains from different insect cecropins
Autor(es): Plunkett, Richard M.; Murray, Stuart I.; Lowenberger, Carl A.
Resumo: The search for new antimicrobial compounds involves finding novel sources of chemotherapeutic compounds or manipulating and combining structures from existing molecules. Small antimicrobial peptides (AMPs) are components of innate immune defenses characterized in greatest detail in insect-derived AMPs. We have generated hybrid AMPs (hAMPs) by combining functional motifs from different insect AMPs as a proof of principle that we can generate molecules with lower minimum inhibitory concentrations, and with different activity and target specificity than either parent molecule. A two-helix, cecropin-like hAMP was created by linking the N-terminal a helix of cecropin A from Aedes aegypti to the C-terminal a helix of cecropin A1 from Drosophila melanogaster. This molecule exhibits antibacterial activity at sub-micromolar concentrations with a target specificity that differs from either parent molecule. Antibacterial activity of the hybrid molecule was found to be greater against Gram-negative than Gram-positive bacteria. No hemolysis was observed in sheep red blood cells exposed to concentrations up to 50 kmol/L, suggesting the peptide is not detrimental to eukaryotic cells.Original Abstract: La recherche de nouveaux composes antibiotiques implique la decouverte de nouvelles sources de composes chimiotherapiques ou la manipulation et la combinaison de structures de molecules existantes. Les petits peptides antimicrobiens (PPA) sont des composantes de la defense immunitaire innee, dont il existe une caracterisation tres detaillee chez l'insecte. Nous avons genere des PPA hybrides (hPPA) en combinant des motifs fonctionnels identifies chez differents PPA d'insectes comme preuve de principe de la generation de molecules possedant des concentrations inhibitrices minimales plus faibles, et des activites et des specificites envers des cibles differentes de celles des molecules d'origine. Une PPA a double helice semblable a la cecropine a ete creee en attachant l'helice-a de l'extremite N-terminale de la cecropine A de Aedes aegypti a l'helice-a de l'extremite C-terminale de la cecropine A1 de Drosophila melanogaster. Cette molecule possede une activite antibacterienne a des concentrations sous-micromolaires et une specificite envers des cibles differentes de celles des deux molecules parentes. L'activite antibacterienne de la molecule hybride est plus elevee envers les bacteries Gram-negatives que Gram-positives. Aucune hemolyse des erythrocytes de mouton exposes a des concentrations allant jusqu'a 50 kmol/L n'a ete observee, ce qui suggere que le peptide n'est pas dommageable pour les cellules eucaryotes.
Palavras-Chave: Hybrid antimicrobial peptides; Cecropin; Antimicrobial activity; Fusion expression
Imprenta: Canadian Journal of Microbiology, v. 55, n. 5, p. 520-528, 2009.
Descritores: Aedes aegypti - Cell ; Aedes aegypti - Vaccine ; Aedes aegypti - Immunology ; Aedes aegypti - Public health
Data de publicação: 2009
