Comparison of two methods of purifying recombinant VacA-HpaA fusion protein inclusion bodies of Helicobacter pylori.

Objective To compare the effect of purification of recombinant VacA-HpaA fusion protein of Helicobacter pylori from inclusion bodies by gel slices and Ni2+-NAT chromatography, and to explore a simple method for purifying recombinant protein from inclusion bodies.MethodsThe recombinant bacteria pQE30-vacA-hpaA-DH5α were cloned and expressed. Inclusion bodies of recombinant VacA-HpaA fusion protein obtained were purified by gel slices and Ni2+-NAT chromatography, respectively.Antigenicity of soluble recombinant protein obtained was identified by Western blot, and immunogenicity of soluble recombinant protein was identified by testing the anti-VacA, anti-HpaA and anti-VacA-HpaA IgG of BALB/c mice immuned with soluble recombinant protein by ELISA.ResultsTwo methods both can purify recombinant VacA-HpaA fusion protein from inclusion bodies. The soluble recombinant VacA-HpaA fusion protein was obtained; purity and yield were 95.8% and 63.5% by Ni2+-NAT chromatography; 93.3% and 75.2% by gel slices, respectively.Western blot confirmed that both soluble recombinant VacA-HpaA fusion proteins had satisfactory antigenicity. Immune serum of BALB/c mice all could be bond with the recombinant protein VacA, HpaA and VacA-HpaA. The difference of IgG level hadn′t statistical significance(P0.05), which showed that the recombinant VacA-HpaA fusion protein both had the satisfactory immunogenicity.ConclusionPurification of the recombinant VacA-HpaA fusion protein from inclusion bodies in gel slices is a relatively simple, effective, economic, useful and practical method, which could be put into purification for protein from inclusion bodies.