Molecular cloning, peptide synthesis and bioactive assessment of a skin defensive peptide, QUB-3055 from the skin secretion of Hylarana latouchii

Antimicrobial peptides (AMPs) which are the most promising substances to be the next antimicrobial reagents are being continuously studied. In this research, we obtained QUB-3055 precursor-encoding cDNAs from skin secretions of Hylarana Latouchii by molecular cloning, then obtained mature peptides by solid-phase synthesis, purified by high-performance liquid chromatography and verified by MALDI-TOF to ensure that the synthesised pure peptide is QUB-3055.

After this, we carried out antimicrobial, haemolytic and anticancer experiments on the pure peptide to analyse the corresponding activity of this peptide. Finally, it was found that QUB-3055 showed strong antimicrobial effects against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), as the minimum inhibitory concentration (MIC) of QUB-3055 against S. aureus is 1 μM and the MIC of QUB-3055 against E. coli is 4 μM, but it had no obvious effect on Candida albicans (C. albicans) at a concentration of 256 μM. Its haemolytic activity is less than 10% at a concentration that exerts an antimicrobial effect.