The functional evaluation of a bioactive peptide, QUB-1998, discovered from the skin secretion of the frog, Pelophylax nigromaculata

Through decades of investment, peptides have been proven to be one potential group of biologics that may contribute to the development of new antibacterial drugs, as they combine the advantages of both small molecule medicines and therapeutic proteins.<br>Through molecular cloning, the cDNA sequence encoding a new antimicrobial peptide (AMP), named QUB-1998, has been identified in the skin secretion of Pelophylax nigromaculata.

The peptide was synthesised using Solid Phase Peptide Synthesis technology. After the identification/authentication of the synthetic replicate of QUB-1998 by High Performance Liquid Chromatography (HPLC) and Matrix-assisted, laser desorption, ionisation, time-of-flight (MALDI-TOF) mass spectrometry, QUB-1998 was subjected to functional tests and it was found to have potent antimicrobial effects against E. coli (MIC = 16 µM; MBC = 32 µM), S. aureus (MIC = 8 µM; MBC = 32 µM), and C. albicans (MIC = 32 µM; MBC = 32 µM).<br>Meanwhile, its haemolytic activity on horse erythrocytes was lower than 20% at 16 µM. The selective antimicrobial effects that observed indicated that QUB-1998 might deserve further exploration.<br>