The discovery and bioactivity evaluation of a novel peptide, QUB-2652, from the skin secretion of the South American frog, Phyllomedusa palliata

  • Ziyi Dong

Student thesis: Masters ThesisMaster of Philosophy


In recent years, the antibiotic resistance of bacteria has stimulated the development of new antibiotics. Antimicrobial peptides (AMPs) from amphibian skin secretions possess broad-spectrum antimicrobial activities through the mechanism that is unlikely to induce antibiotic resistance. Thus, AMPs are great candidates for new antibiotics.
In this study, the precursor-encoding cDNA sequence of QUB-2652 was identified in the skin secretion of Phyllomedusa palliata by ‘Shotgun’ cloning. Then, QUB-2652 was synthesised by solid phase peptide synthesis (SPPS) according to its translated putative mature peptide sequence. After authenticated by Matrix-assisted laser desorption/ionisation Time-of-flight mass spectrometry and purified by Reversed-phase high performance liquid chromatography, the pure QUB-2652 was finally subjected to some functional tests.
According to the BLAST analysis, QUB-2652 showed high sequence similarity with dermaseptins. Results of functional tests showed that QUB-2652 possessed prominent antimicrobial activities against E. coli, S. aureus and C. albicans with the minimum inhibitory concentrations of 2, 2 and 1 µM, respectively. QUB-2652 also showed strong anti-proliferative effects on NCI-H157, PC-3 and U251MG cell lines. Meanwhile, the haemolytic activity of QUB-2652 on horse erythrocytes was 3.6% at 1 µM and 10.6% at 2 µM.
This study is expected to inspire further studies on peptides from frog skin secretions and provide useful clues for developing new peptide antibiotics and anticancer drugs.
Date of AwardJul 2018
Original languageEnglish
Awarding Institution
  • Queen's University Belfast
SupervisorLei Wang (Supervisor), Lei Li (Supervisor), Tianbao Chen (Supervisor) & Christopher Shaw (Supervisor)

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