Cloning and expression of Helicobacter pylori Neutrophil-activating protein fused to the 6xHis tag in Escherichia coli

Abstract

Helicobacter pylori (Hp) has been strongly implicated as a causative factor in peptic ulcer disease, and in significantly increasing the risk of developing gastric cancer. Commercial vaccines nowadays have shown less efficiency on preventing the disease caused by Hp. Therefore, this study was performed to clone nap gene from Hp and over-express the encoded protein (NAP) in E. coli cells. NAP (Neutrophil-activating protein) has been considered as a potential antigen of Hp, can be used to produce peptic ulcer prevention vaccine. The obtained results showed that E. coli OmniMAX and E. coli BL21 (DE3) strains carrying recombinant plasmid pET11a-nap were cloned successfully and remained stable in medium supplemented with ampicillin. Over-expression of NAP protein fused with 6xHis in E. coli was demonstrated via SDS-PAGE and Western blot. The result revealed that the highest target protein production level (29.73%) was obtained in the medium added 0.5 mM IPTG at 37 oC after 6 hours of induction. This is the preliminary research for over-production and purification of Hp-NAP protein that may be used in further applications.