Peptide agents are often considered as potential biomaterials for developing new drugs that can overcome the rising resistance of pathogenic micro-organisms to classic antibiotic treatments. One key source of peptide agents is amphibian skin, as they provide a great deal of naturally occurring antimicrobial peptide (AMP) templates awaiting further exploitation and utilization. In this study, 12 novel AMPs from the skins of 3 ranid frogs,Rana limnocharis,R. exilispinosa,andAmolops afghanus,were identified using a 5′ PCR primer. A total of 11 AMPs exhibited similarities with currently known AMP families, including brevinin-1, brevinin-2, esculentin-1, and nigrocin, besides, one AMP, named as Limnochariin, represented a novel AMP family. All 12 AMPs contain a C-terminus cyclic motif and most of them show obvious antimicrobial activities against 18 standard and clinically isolated strains of bacteria, including 4 Gram-positive bacteria, 11 Gram-negative bacteria, and 3 fungus. These findings provide helpful insight that will be useful in the design of anti-infective peptide agents.
12 novel peptides with broad-spectrum antimicrobial activities were identified from the skin of three frogs. A novel antimicrobial peptide family, named as Limnochariin, were characterized for the first time. Amphibian skin peptides provide novel templates for developing new drugs that can overcome the rising resistance of pathogenic microorganisms to classic antibiotic treatments.