刚地弓形虫P30(SAG1)重组抗原的高效表达和体外纯化(英文)

Over-expression and purification of the recombinant p30 antigen of Toxoplasma gondii

目的表达和纯化弓形虫P30(SAG1)蛋白,为弓形虫病快速诊断试剂盒及蛋白质疫苗的研制奠定基础。方法PCR法从弓形虫基因组DNA中扩增P30基因片段,P30产物克隆到表达质粒pET-30a(+)构建重组载体,将其转化到DH5α中。经PCR扩增和质粒酶切及基因测序鉴定后,阳性重组质粒转化到大肠埃氏菌BL21(DE3)中,经IPTG诱导,表达产物用SDS-PAGE和Western blot进行鉴定。大量的诱导表达产物用SNBC3S NTA Resin方法纯化并进行复性。结果扩增的P30基因片段为750bp,重组表达融合蛋白量单位为30ku,与理论值相符。结论成功构建重组体,获得纯化和复性的弓形虫主要表面抗原P30的高效表达产物,为弓形虫病的诊断和疫苗研究奠定了基础。

To provide the basis for preparation of diagnostic kits and vaccines in Toxoplasma gondii infection, the gene coding for the qualified recombinant p30 protein （ SAG1 ） of this parasite was amplified by PCR, and the amplified gene was cloned into prokaryotic expression vector pET-30a（ ＋ ） to construct the recombinant plasmid, and then transformed to E. coli DH5a. The positive recombinant plasmid was screened by PCR and double enzymes digestion, and the nucleotide sequence of p30 gene was determined by automated DNA sequencing. Meanwhile, the identified recombinant plasmid was transformed to E. coli BL21（DE3） with the expression of p30 on bacteria induced by IPTG and the expressed protein was identified by SDS-PAGE. The protein obtained was then further purified and refolded, and its biological activity was checked by Western blotting. It was shown that the size of the amplified gene was 750 bp with molecular weight of 30 ku, and this protein could specifically react with monoclonal antibody against p30 protein.