Cloning, expression, and purification of HpaA-CagA fusion recombinant protein of Helicobacter pylori in E. coli BL 21 strain

Helicobacter pylori colonizes in the stomach of nearly half of the world's population. It is one of the most common causes of chronic bacterial infection and a well-known risk factor for gastric cancer in humans. This study aimed to evaluate the cloning, expression, and purification of the HpaA-CagA fusion recombinant protein of H. pylori in E. coli BL21 (DE3) strain. The HpaA-CagA construct was designed using bioinformatics tools. The construct was then sub-cloned to the pET21b prokaryotic expression vector. Then, E. coli BL21 (DE3) was transfected with the pET21b-HpaA-CagA. Then, E. coli BL21 (DE3) was transformed with pET21b-HpaA-CagA. The gene expression was induced by IPTG. The protein expression was verified using SDS page and western blot analysis. The recombinant protein was finally purified using nickel nitrilotriacetic acid (Ni-NTA) resin. The waste materials were removed by dialysis. The concentration of recombinant protein was determined by the Bicinchoninic Acid Protein Assay Kit (Parstoos). In this study, HpaA-CagA was sub-cloned into the pET21b vector. The expression of the recombinant protein was confirmed in the host. The recombinant protein with the weight of 69 kDa was successfully purified. We here presented an efficient method to construct, clone, express, and purify the HpaA-CagA recombinant protein. The recombinant HpaA-CagA protein showed immunogenicity feature with human antiserum. © 2019 Elsevier Inc