High-level expression of fusion peptide Dybowskin-2CDYa and hEGF in E. coli and its dual function

Abstract

Dybowskin-2CDYa (Dy2), with a broad antimicrobial spectrum and low hemolytic feature, is a newly discovered type of antimicrobial peptides from Rana dybowskii. In order to get a dual function peptide which inhibits bacterial growth and promotes cell proliferation, we cloned the gene of Dy2and hEGF (human epidermal growth factor) into the prokaryotic expression vector pET-30a(+). With isopropyl-β-D-thiogalactoside (IPTG) induction, a 13.7KDa peptide with a 6×His tag was highly expressed in the form of inclusion in E. coli BL2l (DE3). SDS-PAGE and westernblot confirmed the expression of the fusion peptide hEGF-Dy2. Under the optimized condition of 1.0mmol/L IPTG induction and incubation time 4h at 37o, the yield of hEGF- y2reached 30mg/L following purification on nickelnitrilotriacetic acid (Ni-NTA) metal affinity chromatography matrices. The purified fusion peptide showed significant antibacterial activities against Staphylococcus aureus, Escherichia coli O157, Pseudomonas aeruginosa and proliferating activities on NIH3T3. These results indicated that the fusion peptide might have a good prospect in therapy of trauma and burns.