Evaluation of bioactivity of a peptide QUB-1669, from the skin secretion of the African running frog, Kassina senegalensis

Abstract

Biologically-active peptides are widely present in amphibians. They not only play an essential role in the host's physiological system but also in the research and development of new drugs for mammals. Many amphibian skin-derived peptides have been proven to have clinically-valuable activities, including antibacterial effects, anticancer effects, enzyme inhibitor effects, smooth muscle inhibition or relaxation effects, etc., and they are also the current research hotspots of many scientists.

In this experimental study, a new pharmacologically active peptide QUB-1669 was studied. This is a C-terminal amidated peptide (FFPLALPLPKATKVQ-amide) identified from the skin secretion of the African running frog Kassina senegalensis. To obtain the mature peptide sequence, a K.senegalensis skin secretion-derived cDNA library was constructed and then subjected to molecular cloning experiments. Thereafter, the obtained sequence of peptide QUB-1669 was chemically synthesised by solid phase peptide synthesis (SPPS), and then the synthesised crude peptide was purified by reversed-phase high-performance liquid chromatography (RP-HPLC), along with mass spectrometry. Finally, the purified peptide was used to explore functional activity by using a range of bioassays such as antibacterial, antiproliferation, haemolysis and smooth muscle. The results showed that QUB-1669 peptide had potent effects on rat ileum smooth muscle and uterine smooth muscle at low concentrations of 10-11M without lysing horse red blood cells. This peptide had no inhibitory effects on three test microorganisms, including the Gram-positive bacterium (S. aureus), the VII Gram-negative bacterium (E. coli) and the yeast (C. albicans). In addition, no antiproliferation effects on cancer cells were observed. This frog species has not been extensively studied so far, so this study has contributed partly to the study of peptides from the skin secretion of Kassina senegalensis.

Date of Award	Dec 2020
Original language	English
Awarding Institution	Queen's University Belfast
Supervisor	Mei Zhou (Supervisor) & Lei Wang (Supervisor)