Objective    To construct the fusion gene of H.pylori outer membrane protein AhpC

UreB414 and E.coli heat-labile enterotoxin B subunit.     Methods    We constructed the fusion gene aul including ahpC

ureB414 and ltB gene by SOE PCR (splicing by overlap extension)

setting AhpC gene before UreB414-ltB fusion gene and  introducing a fixible linker GGGGS between them. Then the aul gene was constructed into the expression plasmid pET-22b(+). The fusion protein

was expressed in E.coli BL21 induced by IPTG

confirmed by SDS-PAGE and Western blotting. The inclusion body was purified with AKTA-explore 100 system after washing.      Results    The fusion gene was successfully cloned into pET-22b(+). The gene segment inserted into the recombinant vector was identified by restriction enzyme digestion and sequencing

and proven to be consistent with that in GenBank. The relative molecular weight of the expressed product was 50×10

3

. The purity of rAUL was up to 85% after Chelating Sepharose affinity chromatography.      Conclusion    The fusion proteins rAUL and rLUL were constructed and expressed successfully. The fusion proteins retain the immunoreactivity of each of their components as well as the binding activity with GM1 ganglioside.