Fusion expression of the PGLa-AM1 with native structure and evaluation of its anti-Helicobacter pylori activity

Helicobacter pylori (H. pylori) shows increasingly enhanced resistance to various antibiotics， and its eradication has become a major problem in medicine. The antimicrobial peptide PGLa-AM1 is a short peptide with 22 amino acids and exhibits strong antibacterial activity. In this study， we investigated whether it has anti-H. pylori activity for the further development of anti-H. pylori drugs to replace existing antibiotics. However， the natural antimicrobial peptide PGLa-AM1 shows a low yield and is difficult to separate， limiting its application. A good strategy to solve this problem is to express the antimicrobial peptide PGLa-AM1 using gene engineering at a high level and low cost. For getting PGLa-AM1 with native structure， in this study， a specific protease cleavage site of tobacco etch virus (TEV) was designed before the PGLa-AM1 peptide. For convenience to purify and identify high-efficiency expression PGLa-AM1， the PGLa-AM1 gene was fused with the polyhedrin gene of Bombyx mori (B. mori)， and a 6 × His tag was designed to insert before the amino terminus of the fusion protein. The fusion antibacterial peptide PGLa-AM1 (FAMP) gene codon was optimized， and the gene was synthesized and cloned into the Escherichia coli (E. coli) pET-30a (+) expression vector. The results showed that the FAMP was successfully expressed in E. coli. Its molecular weight was approximately 34 kDa， and its expression level was approximately 30 mg/L. After the FAMP was purified， it was further digested with TEV protease. The acquired recombinant antimicrobial peptide PGLa-AM1 exerted strong anti-H. pylori activity and therapeutic effect in vitro and in vivo.