炭疽毒素保护性抗原第四结构域在大肠杆菌中的可溶性表达

人工优化设计并合成炭疽毒素保护性抗原第四结构域基因，并与噬菌体gⅢ蛋白N端结构域基因融合，在大肠杆菌中可溶性表达融合蛋白。结果表明合成了炭疽毒素保护性抗原第四结构域基因，并在大肠杆菌中获得了高效可溶性融合表达，可溶性表达产物占细菌总蛋白量的36％左右；经亲和层析纯化获得了重组蛋白；Western印迹分析表明，表达产物能与His单抗（重组蛋白羧基端带有6xHis）发生特异性结合反应。以上结果表明获得了炭疽毒素保护性抗原第四结构域，为利用人抗体库进行筛选抗炭疽毒素的人源性中和抗体奠定了基础。

Soluble Expression of Domain 4 of the Protective Antigen of Anthrax Toxin in E. coli

The domain 4 gene sequence of the protective antigen of anthrax toxin was optimized for soluble expression in E.coli, synthesized by fragments and assembled by overlapping extension PCR, then it was fused with the gene of N1-domain of g 111 protein of filamentous phage M13, and the fusion protein was expressed in E.coli as soluble protein form. The domain 4 gene of the protective antigen of anthrax toxin was obtained, and the recombinant fusion protein was about 36% in total proteins and the purity was high by Ni-NTA affinity chromatography. Western-blot analysis showed the recombinant protein can be recognized by His monoclonal antibody. This work provides basis for selecting human neutral antibodies to anthrax toxin from the human antibody libraries.