Discovering Antimicrobial Peptides in Red-Legged Salamander Skin Secretions using De Novo Protein Sequencing

Abstract

Antibiotic resistance has emerged as a major global health challenge due to the overuse and misuse of antibiotics. Previous studies have investigated the antimicrobial properties of frogs and toads as potential sources of novel therapeutics for combating antibiotic-resistant bacteria. Salamanders, including the red-legged salamander examined in this study, produce antimicrobial skin secretions that protect them from harmful bacteria and fungi in their environment. However, comparatively little is known about the peptide composition of salamander skin secretions. In this study, proteins were extracted from red-legged salamander skin secretions and analyzed using nano liquid-chromatography mass spectrometry (nanoLC-MS/MS). Peptides were identified through de novo sequencing using PEAKS software, and putative antimicrobial peptides were predicted using antimicrobial peptide (AMP) prediction tools, including CAMP-R3 and AMP Scanner. Across four sample injections, 135 unique peptides were identified, of which 36 were predicted to possess antimicrobial activity. These candidate peptides represent promising targets for further investigation. Future studies will evaluate their antimicrobial activity against bacterial and fungal pathogens and assess their potential as lead compounds for the development of novel therapeutics to combat antibiotic-resistant infections.