Identification and functional study of a novel bioactive peptide QUB-1761 from the venom of the Brazilian yellow scorpion, Tityus serrulatus

Abstract

Scorpion venom contains a variety of peptides exerting broad bioactivities. In this thesis, QUB-1761, a non-disulphide bridged peptide (NDBP), was discovered in the venom of the Brazilian yellow scorpion, Tityus serrulatus (T. serrulatus). The peptide was identified through molecular cloning by using a sense primer. The synthetic peptide was obtained by solid phase peptide synthesis (SPPS), followed by purification and confirmation through reversed-phase high performance liquid chromatography (RP-HPLC) and matrix-assisted laser desorption ionisation-time of flight mass spectrometry (MALDI-TOF MS). In broth microdilution assays, QUB-1761 had strong inhibitory effects on both Gram-positive and Gram-negative bacteria (MIC=8 µM for Staphylococcus aureus, MIC=32 µM for Escherichia coli). However, it was of low potency against yeast (MIC=128 µM for Candida albicans). In MTT anticancer cell proliferation and trypan blue exclusion assays, QUB-1761 beyond the concentration of 40 µM can completely kill the human lung cancer cells (NCI-H838). In terms of the haemolytic assays, QUB-1761 showed about 30% haemolysis activity at 64 µM and more than 50% at 128 µM. Nonetheless, QUB-1761 has the potential to be used in the design of drugs to treat bacterial infections or cancer if optimised.

Thesis embargoed until 31 December 2026.

Date of Award	Dec 2021
Original language	English
Awarding Institution	Queen's University Belfast
Sponsors	Queen's University & China Scholarship Council
Supervisor	Mei Zhou (Supervisor), Tianbao Chen (Supervisor), Lei Wang (Supervisor) & Yuan Ying (Supervisor)