Identification and bioactivity evaluation of an amphibian skin Bowman-Birk-like trypsin inhibitor from Hylarana nigrovittata

Abstract

As a result of fighting fungal and microbial infections in their living environment, granular glands of amphibian skin can produce various compounds, especially peptides and proteins, which are useful for preventing bacterial and fungal infections. Among these bioactive compounds, serine protease inhibitors have been found in amphibian skin. Serine proteases are a large family of conserved, proteolytic enzymes. They play a role in many bodily functions and some are digestive enzymes. Protease action can be controlled by protease inhibitors, therefore protease inhibitors also get involved in regulating numerical physiological problems and are considered as a treatment of human diseases. In this study, a novel peptide (SALVGCWTKSIPPKPCF) of the Bowman-Birk inhibitor family, was found in the skin secretion of Hylarana nigrovittata, and was named QUB-1832. Its biosynthetic precursor-encoding cDNA was cloned by using a ‘shotgun’ cloning technique to deduce its primary structure. Thereafter, a corresponding synthetic replicate was synthesized by solid-phase Fmoc chemistry. Through a series of experiments, QUB-1832 was found to display inhibition activity against trypsin and anticancer activity against lung cancer cell (H23) and prostate cancer cell (PC-3), along with a negligible haemolytic effect. However, QUB-1832 was found to have no antimicrobial activity, therefore, in further study, QUB-1832 can be modified to achieve multifunctional peptides with antimicrobial activity.

Thesis embargoed until 31st October 2024

Date of Award	Dec 2019
Original language	English
Awarding Institution	Queen's University Belfast
Supervisor	Tianbao Chen (Supervisor), Mei Zhou (Supervisor), Lei Wang (Supervisor) & Yuxin Wu (Supervisor)