Identification and bioactivity evaluation of a novel peptide, QUB-2099, from the skin secretion of the bamboo leaf odorous frog, Odorrana versabilis

As the problem of antibiotic resistance gets worse, the need to search for novel antimicrobial molecules is high on the agenda. Antimicrobial peptides (AMPs) derived from amphibian defensive skin secretions have been found to possess remarkable bioactivities, therefore, AMPs are recognised as one of the most promising groups of molecules for potential therapeutic applications.<br><br>In this study, the precursor peptide of QUB-2099 was identified from the skin secretion of Odorrana versabilis using ‘shotgun’ cloning and its encoded mature peptide, and was synthesised by solid phase peptide synthesis.

The structure of the synthetic peptide was confirmed by matrix-assisted laser desorption/ionisation time-of-flight (MALDI-TOF) mass spectrometry and purified by reversed-phase high performance liquid chromatography (RP-HPLC). To evaluate the bioactivity of QUB-2099, several assays were conducted, including antimicrobial assays, cell viability assays, and haemolysis assays. The results revealed that QUB-2099 exhibited antimicrobial activity against S. aureus (MIC=16µM), MRSA (MIC=128µM), E. coli (MIC=16µM), and P. aeruginosa (MIC=256µM), while showing negligible haemolytic activity and anticancer activity towards NCI-H838 cancer cells.