Gene Cloning,Expression and Purification of BP26 Protein of B. abortus

Objective To clone the BP26 gene of B.abortus,highly express in E.coli and purify the expressed product.MethodsExtract the genomic DNA of B.abortus,amplify BP26 gene by PCR and clone to pMD18-T simple vector.Identify the constructed recombinant plasmid pMDBP26 by sequencing,then subclone to vector pET-28a(+).Transform the constructed recombinant plasmid pETBP26 to E.coli BL21(DE3)for expression under induction of IPTG.Purify the expressed product by histidine-binding resin column chromatography and identify by Western blot.Results Two gene fragments at lengths of 5 400 and 700 bp respectively were obtained by digestion of recombinant plasmid pETBP26 with Nde I+Sal I,which were consistent with the theoretical value.After the transformed E.coli BL21(DE3)was induced at 37℃ for 4 h,SDS-PAGE proved that fusion protein BP26 with His-tag label was highly expressed.The fusion protein reached a purity of 96% after purification and showed antigenic specificity as proved by Western blot.Conclusion BP26 gene was successfully cloned and expressed,and the expressed product was purified.