Antimicrobial peptides (AMPs) are host defence peptides found abundantly in amphibian skin secretions. They have broad antimicrobial spectrum of Gram-positive bacteria, Gram-negative bacteria, fungi and viruses. In this study, skin secretion of the common frog, Rana temporaria, was used to build a cDNA library by mRNA transcription. A cDNA encoding a peptide biosynthetic precursor transcript was consistently cloned from this by “shot-gun” cloning. The precursor peptide sequence was analysed by bioinformatics tools such as NCBI-BLAST, while Uniprot identified the mature peptide sequence (FLPIVGKLLSGLL-NH2). Then, using Fmoc solid -phase peptide synthesis, the peptide chain was assembled stepwise and attached to resin support. After the peptide was assembled, it was removed from the resin to obtain a crude linear peptide. Reverse-phase HPLC was used to obtain a purified peptide and in accordance with its molecular mass obtained by MALDI-TOF MS, the peptide was named QUB-1369. Antimicrobial assays showed that QUB-1369 was active against Gram-positive bacterium, Staphylococcus aureus and the yeast, Candida albicans at concentrations of 8 µM and 128 µM, respectively. It was not active against Gram-negative bacterium, Escherichia coli. Haemolysis assay of QUB-1369 using horse erythrocytes, showed it was active at a concentration of 16 µM. Anticancer assay found a weak inhibition of HCT 116 Human Colon Carcinoma cells at a concentration of 100 µM.
|Date of Award||Dec 2020|
- Queen's University Belfast
|Supervisor||Tianbao Chen (Supervisor), Mei Zhou (Supervisor), Lei Wang (Supervisor) & Xinping Xi (Supervisor)|