关键词: 刚地弓形虫； 表面抗原2； 基因克隆； 融合蛋白； 蛋白纯化

Abstract:

Objective Objective To construct a recombinant plasmid containing surface antigen 2 （SAG2）gene of Toxoplasma gondii and express it in Escherichia coli. Methods Methods The truncated SAG2 gene was amplified from the genomic DNA of T. gondii RH strain and cloned into plasmid pGEX?4T. Then the recombinant pGEX?4T?SAG2 was induced by IPTG and expressed in E. rich? ia coli BL21. The expressed proteins were analyzed by SDS?PAGE and purified，and the immunogenicity of the product was ana? lyzed by Western blotting. Results Results The amplified SAG2 gene was about 561 bp，which was accorded to the expectation. The re? combinant plasmid was constructed successfully by digested with double restriction enzyme and confirmed with DNA sequenc? ing. SDS?PAGE and Western blotting showed the molecular weight of SAG2 fusion protein was about 47 ku，and the protein could be identified by GST?tag antibody. Conclusion Conclusion The truncated SAG2 gene of T. gondii has been successfully cloned and expressed in E. coli BL21 cells，and the recombinant protein has immunogenicity.

Key words: Toxoplasma gondii；Surface antigen 2； Gene clone； Fusion protein；Protein purification