Identification and functional study of a bioactive peptide QUB-1962 from the skin secretion of the yellow-bellied toad (Bombina variegata)

Abstract

Because of the continuous emergence of drug-resistant strains, more and more antibiotics have lost their due role. The antimicrobial peptide has become the most promising substance in the next class of antimicrobial agents. QUB-1962 is a cationic antimicrobial peptide isolated from the skin secretions of Bombina variegata. Using the "shotgun" cloning technique, a novel full-length peptide precursor of the bombinin peptide was cloned from the cDNA library of skin secretion from Bombina variegata. The speculative peptide was identified as QUB-1962 (IIGPVLGMVGNALGGLLKKI-NH2). And the crude peptide of QUB-1962 was obtained by solid-phase synthesis. Then, QUB-1962 was identified in HPLC fractions based on their molecular masses determined by MALDI-TOF MS. In addition, QUB-1962 exhibited a broad-spectrum antimicrobial effect against Gram-positive bacteria Staphylococcus aureus (S. aureus), Gram-negative bacteria Escherichia coli (E. coli), and fungus Candida albicans (C. albicans) and has relatively weak haemolytic activity (HC50 is 691.6 μl). The anti-cancer activity assay showed that the peptide had a significant anti-cancer effect (IC50: 3.471×10-5 M) on the tested human cancer cell glioblastoma U251 MG. According to the data of these biological activities, QUB-1962 has a wide range of biological activities, including antimicrobial and anticancer activities. At the same time, it could be a good candidate for the development of new anti-cancer and antimicrobial infection drugs.

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