乙肝PreS_2抗原决定簇和霍乱毒素B亚基基因的融合与表达

Gene Fusion and Expression of Cholera Toxin B Subunit with HBV PreS_2 Epitope

本研究通过全化学法按大肠杆菌密码偏性合成了HBV PreS_2抗原决定簇基因,与ctxB基因的3’端融合。重组质粒转化大肠杆菌后融合基因得到高效表达,表达量达30μg/ml,表达产物95％以上分泌到胞外。表达的融合蛋白能与神经节苷脂GM1结合,说明融合蛋白保持了CTB的基本高级结构和生物学功能;ELISA实验证明融合蛋白具有CTB和HBV PreS_2的抗原性;应用亲和层析纯化后得到了电泳纯融合蛋白制品,为研究融合蛋白的免疫原性并进一步构建基因工程肽苗奠定了基础。

Nucleotides encoding 120-145aa epitope of HBV PreS2 were chemically synthesized according to the codon usage frequency of E. coli and genetically fused to the 31 end of cholera toxin B subunit(CTB) gene. The fused gene was expressed (about 30 ug/ml)in E. coli, and more than 95 % of the fusion protein could be secreted into the medium. The fusion protein was purified by affinity chromatography. It had been demonstrated that the chimera obtained could bind to ganglioside GM1, which indicated that it retained the biological function of CTB. The chimera had the antigenicity both for CTB and HBV PreSz confirmed by ELBA. This work provide a sound basis for further studies on the immunogenicity of fusion protein and on the construction of engineered peptide vaccine.