炭疽毒素受体CMG2胞外区的截短表达、纯化及鉴定分析

Study on the truncated expression of purification and identification extracellular region of anthrax toxin receptor CMG2

【目的】分析CMG2胞外区的分子结构与功能,探讨ATR与PA结合的活性位点及特征,为阐明炭疽毒素的致病机理提供依据。【方法】用pQE30表达质粒在大肠杆菌内表达长短不同的3个CMG2胞外区截短片段,经纯化后,用Western blotting和细胞保护性实验对3个重组蛋白进行分析。【结果】发现3个重组蛋白均可与4B5单抗结合,但均没有细胞保护活性。【结论】3个截短蛋白失去了与PA结合的能力,说明CMG2的187～217之间氨基酸残基对PA结合很重要,不可或缺。

[Objective] To analyze the molecular structure and function of capillary morphogenesis protein 2 （CMG2） and investigate the character about binding site of CMG2 with PA for illuminating pathopoiesis of anthrax toxin. [Methods] Genes encoding three truncated domains of CMG2 were cloned into pQE30 vector respectively and induced to express three proteins by IPTG. The recombinant proteins were purified and then identified by cytoprotection assay and Western blotting. [Results] Three recombinant proteins obtained could bind to McAb 4B5, but they lost the cytoprotection activity. [Conclusions] It was concluded that the amino acid residues among 187-217 of CMG2 are essential for bingding PA.