The discovery, rational design, and bioactivity evaluation of antimicrobial peptides from the skin secretions of amphibians

Their main activity and toxicity were affected by hydrophobicity, which significantly increased their safety when hydrophobicity was reduced to the safety threshold. When hydrophobicity is reduced to a safe level, increasing the positive charge significantly improves the antimicrobial activity without increasing haemolysis. The best results were obtained with BH2L-8R15R and BH2L-78K, a modified peptide with multiple bactericidal mechanisms.

In Chapter 5, to investigate the impact of different living habits on the activity of antimicrobial peptides secreted by frogs, a specific species of tree frog was selected as the research subject. QUB-2048 extracted from the skin secretion of Phyllomedusa hypochondrialis azurea, was modified. This is an antimicrobial peptide of similar length to Bombinin-H2L.

The effect of the common modified peptide residues “-PRW-” on the biological activity and spatial structure of this peptide was explored. This will lay the foundation for the rational design of similar peptides of the same family in the future. <br><i><br>Thesis is embargoed until 31 December 2029.</i>