Leptodactylus latrans Amphibian Skin Secretions as a Novel Source for the Isolation of Antibacterial Peptides

SIANO A; HUMPOLA, M.V; SIMONETTA A.C.; LAJMANOVICH, R.C.,; TONARELLI G.

MOLECULES

MOLECULAR DIVERSITY PRESERVATION INTERNATIONAL-MDPI

Lugar: Basel; Año: 2018 vol. 23

1420-3049

Amphibians´ skin produces a diverse array of antimicrobial peptides that play a crucialrole as the first line of defense against microbial invasion. Despite the immense richness of wildamphibians in Argentina, current knowledge about the presence of peptides with antimicrobialproperties is limited to a only few species. Here we used LC-MS-MS to identify antimicrobial peptideswith masses ranging from 1000 to 4000 Da from samples of skin secretions of Leptodactylus latrans(Anura: Leptodactylidae). Three novel amino acid sequences were selected for chemical synthesis andfurther studies. The three synthetic peptides, named P1-Ll-1577, P2-Ll-1298, and P3-Ll-2085, inhibitedthe growth of two ATCC strains, namely Escherichia coli and Staphylococcus aureus. P3-Ll-2085 wasthe most active peptide. In the presence of trifluoroethanol (TFE) and anionic liposomes, it adoptedan amphipathic -helical structure. P2-Ll-1298 showed slightly lower activity than P3-Ll-2085.Comparison of the MIC values of these two peptides revealed that the addition of seven amino acidresidues (GLLDFLK) on the N-terminal of P2-Ll-1298 significantly improved activity against bothstrains. P1-Ll-1577, which remarkably is an anionic peptide, showed interesting antimicrobial activityagainst E. coli and S. aureus strain, showing marked membrane selectivity and non-hemolysis. Due to