title: Mode of action and membrane specificity of the antimicrobial peptide snakin-2.
abstract: Antimicrobial peptides (AMPs) are a diverse group of short, cationic peptides which are naturally occurring molecules in the first-line defense of most living organisms. They represent promising candidates for the treatment of pathogenic microorganisms. Snakin-2 (SN2) from tomato (Solanum lycopersicum) is stabilized through six intramolecular disulphide bridges; it shows broad-spectrum antimicrobial activity against bacteria and fungi, and it agglomerates single cells prior to killing. In this study, we further characterized SN2 by providing time-kill curves and corresponding growth inhibition analysis of model organisms, such as E. coli or B. subtilis. SN2 was produced recombinantly in E. coli with thioredoxin as fusion protein, which was removed after affinity purification by proteolytic digestion. Furthermore, the target specificity of SN2 was investigated by means of hemolysis and hemagglutination assays; its effect on plant cell membranes of isolated protoplasts was investigated by microscopy. SN2 shows a non-specific pore-forming effect in all tested membranes. We suggest that SN2 could be useful as a preservative agent to protect food, pharmaceuticals, or cosmetics from decomposition by microbes.
authors.affiliation: Institute of Pharmacy and Molecular Biotechnology, Ruprecht-Karls-Universität Heidelberg , Heidelberg , Germany.
authors.forename: Vera
authors.initials: V
authors.lastname: Herbel
authors.affiliation: Institute of Pharmacy and Molecular Biotechnology, Ruprecht-Karls-Universität Heidelberg , Heidelberg , Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Wink
keywords: Antimicrobial peptide; Bactericide; Fungicide; Non-specific; Pore-forming activity; Snakin-2