Molecular cloning, peptide synthesis and bioactive assessment of a skin defensive peptide, QUB-3117 from the skin secretion of Rana schmackeri

  • Danni Yong

Student thesis: Masters ThesisMaster of Philosophy


Anurans are the largest group of amphibian and widely distributed in the world. The skin secretion of anurans has been considered as potential candidate for drug development due to its crucial role in protecting from environment. To date, abundant biologically active compounds have been successfully isolated and identified to perform various bioactivities. In this research, a novel peptide was isolated from the skin secretion of the Rana schmackeri by “Shotgun” Cloning. The mature peptide contains 29 amino acid residues (QUB-3117: DYMDTAKNAAKNMAAILLDKLKCKMTGGC). The functional group is carboxyl group at C-terminus. The peptide was temporarily named as QUB-3117 and it was speculated as the member of plaustrin-2 family according to the result of bioinformatics analysis. The peptide was chemically synthesized by Solid Phase Peptide Synthesis and purified by RP-HPLC. It was identified by MALDI-TOF MS, which shows identical molecular weight with theoretical value. The functional assay was carried out on the purified peptide. In the minimum inhibitory concentration assay, the QUB-3117 performed little antimicrobial activity against S. aureus (ATCC CRM 6538), E. coli (NCTC 10418) and C. albicans (ATCC 10231) with the MIC value of over 512 µM for each microbe. However, the peptide showed significant inhibition on the growth of PC-3 prostate cancer cell line and non-small cell lung cancer H838 cell line, with the half maximal inhibitory concentration (IC50) of 1.48×10-4M and 1.81×10-4M, respectively. It also showed little activity against erythrocyte from horse blood with HC50 values of over 512 µM. Therefore, considering the significant inhibition on tumor cells and little cytotoxicity against erythrocyte, QUB-3117 possess the potential to be developed as drug candidate.
Date of AwardDec 2020
Original languageEnglish
Awarding Institution
  • Queen's University Belfast
SupervisorMei Zhou (Supervisor), Lei Wang (Supervisor) & Xinping Xi (Supervisor)

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