Cysteine Auxotrophic Expression and Identification of Antiviral Selenium-containing Peptide

Abstract

Objective: To express the soluble antiviral peptide,the cysteine auxotrophic expression system was used in Escherichia coli( E. coli). And the biological activities of the purified antiviral peptide were initially identified. Method: The gene sequence of antiviral peptide Se-GBVA10 was chemically synthesized according to the optimized codons of E. coli,and the gene was cloned into GST fusion expression vector pGEX-2T. Then,the plasmid pGEX-2T-GBVA10 was converted to cysteine auxotrophic expression strains( E. coli BL21cysE51). Expressed proteins were purified by glutathione Sepharose 4B affinity column. Finally,the content of selenium, the antiviral activity and the antioxidant activity( the vitality of glutathione peroxidase) of the antiviral peptides were detected. Results: The fusion protein,sjGST-Se-GBVA10 and sjGST-GBVA10,were successfully expressed by means of cysteine auxotrophic expression system. After cutting with thrombin,the purified antiviral peptides, Se-GBVA10 and GBVA10 were obtained. The content of selenium of the Se-GBVA10 was 0. 974 mol / mol peptide,the glutathione peroxidase vitality of Se-GBVA10 was 47. 52 U / μmol,the concentration for 50% of maximal effect( EC50) of Se-GBVA10 was 21. 73μmol/L,and the median cytotoxic concentration( CC50) of SeGBVA10 was 849. 41μmol / L. Conclusion: The antiviral peptide Se-GBVA10 has the same antiviral activity as the GBVA10,but also has some antioxidant activity.