Peptides with antimicrobial activity from four different families isolated from the skins of the North American frogs Rana luteiventris, Rana berlandieri and Rana pipiens

Abstract

The skins of frogs of the genus Rana synthesize a complex array of antimicrobial peptides that may be grouped into eight families on the basis of structural similarity. A total of 24 peptides with differential growth-inhibitory activity towards the Gram-positive bacterium Staphylococcus aureus, the Gram-negative bacterium Escherichia coli and the yeast Candida albicans were isolated from extracts of the skins of three closely related North American frogs, Rana luteiventris (spotted frog), Rana berlandieri (Rio Grande leopard frog) and Rana pipiens (Northern leopard frog). Structural characterization of the antimicrobial peptides demonstrated that they belonged to four of the known families: the brevinin-1 family, first identified in skin of the Asian frog Rana porosa brevipoda; the esculentin-2 family, first identified in the European frog Rana esculenta; the ranatuerin-2 family, first identified in the North American bullfrog Rana catesbeiana; and the temporin family, first identified in the European frog Rana temporaria. Peptides belonging to the brevinin-2, ranalexin, esculentin-1 and ranatuerin-1 families were not identified in the extracts. Despite the close phylogenetic relationship between the various species of Ranid frogs, the distribution and amino-acid sequences of the antimicrobial peptides produced by each species are highly variable and species-specific, suggesting that they may be valuable in taxonomic classification and molecular phylogenetic analysis.

Predicted Disease Susceptibility in a Panamanian Amphibian Assemblage Based on Skin Peptide Defenses

“…Similarly, some Rana pipiens mass signals matched previously described antimicrobial peptides of the brevinin 1 family (m/z 2,563, 2,577, and 2,593) and ranatuerin-2P (m/z 3,000) ( Fig. 1B; Goraya et al, 2000). Thus, natural mixtures of peptides from some species analyzed here contained conventional antimicrobial peptides.…”

Systematic Peptide Engineering and Structural Characterization to Search for the Shortest Antimicrobial Peptide Analogue of Gaegurin 5

“…1): the hydrophobic N terminus (residues 1-4), the C-terminal cyclic loop (residues 18 -24) by a conserved disulfide bond, and the body of an amphipathic ␣-helix (residues 3-20) kinked at Pro 14 . The N-terminal hydrophobic region has been suggested to anchor the peptide within the membrane, whereas a Amino acid sequences are represented by the corresponding sample numbers (refer to Fig.…”

“…Several antimicrobial peptides such as magainin, a 23-residue antimicrobial peptide, have been successful in pharmaceutical and commercial development (5). Particularly, from the first discovery of bombinins in Bombina variegata (7), the skin of anurans (frogs and toads) has proven to be a rich source of peptides with a broad spectrum of antimicrobial activities (6,8,14). After the discovery of the magainins in 1987 (15), attention has been increasingly focused upon amphibian skin peptides as potential therapeutic agents (2,5,6).…”

Antimicrobial peptides from amphibians

“…Magainins (16), ranatuerin-2, temporin families (63,64) and dermaseptins (25) adopt an amphipathic a-helial conformation, either in aqueous solution or upon interaction with membranes of microorganisms (64). However, ranatuerin-1, aurein 1.2 and caerin 1.1 from Australian frog adopt random coil arrangement in aqueous solution and an a-helical structure in membrane mimetic environments (65)(66)(67)(68)(69).…”

“…Brevinin-1, brevinin-2, esculentin-1 and esculentin-2 AMP families, which are found in many Ranidae amphibians, exhibit high potency on a wide range of Gram-positive bacteria, Gram-negative bacteria and fungi (1,23,64,80). For example, esculentin-1 showed strong antimicrobial activities against a range of human pathogens such as E. coli, S. aureus, Pseudomonas aeruginosa and Caenorhabditis albicans.…”