Molecular cloning, peptide synthesis and bioactive assessment of a skin defensive peptide, QUB-2658 from the skin secretion of <i>Limnonectes fujianensis</i>

Antimicrobial peptides (AMPs) from amphibian skin secretion were found to have excellent broad-spectrum antibacterial activities and inhibit drug-resistant bacteria, which made AMPs a potential new antibacterial drug source. Frog skin secretions are the most abundant source of AMPs and thus they have been widely studied by researchers. <br><br>In this study, a novel peptide (with an 훼-helix structure) named QUB-2658 (ANMFEDLKNVIKLVEQDRPVLSV-NH2) which does not belong to any known peptide family, has been isolated from the skin secretion of Limnonectes fujianensis.

From the same skin secretion, a cDNA library was constructed and subjected to RACE-PCR. The peptide biosynthetic precursor-encoding cDNA sequence was obtained using molecular cloning and Sanger Sequencing. The mature peptide was synthesized by solid phase peptide synthesis, identified and purified by MALDI-TOF mass spectrometry and reverse phase High Performance Liquid Chromatography.