重组变形链球菌V+蛋白的表达和纯化

目的：探讨变形链球菌表面蛋白可变区（V＋）基因在大肠杆菌中高效诱导表达及其表达产物的进一步纯化。方法：将V＋基因以C端融合6个组氨酸的形式在E.coli BL21(DE3)中进行IPTG诱导表达。His6融合表达产物经金属离子（Ni^2 )融体亲和层析分离纯化，SDS－PAGE电泳和Western blot印迹分析表达产物。结果：SDS－PAGE分析确定有与His6融合表达产物（His6-rV )理论相对分子质量一致的诱导表达条带，其表达量占全菌蛋白的20％左右，表达产物以可溶形式存在。进一步纯化目的蛋白，纯度可达90％。Western blot实验表明表达产物具有良好的抗原性。结论：His6融合表达载体可以高效地表达和纯化重组V＋蛋白。

Expression and purification of recombinant V+protein of Streptococcus mutans

Objective To explore high level expression and purification of recombinant V+protein of the Streptococcus mutans in E.coli. Methods V+gene was cloned into a His 6 fusion expression vector.After transforming into E.coli BL21(DE3),His 6 rV+was induced to express by IPGT.The expression product with His 6 Tag was purified by immobilized metal (Ni 2+ )chelation affinity chromatography.The expression product was analyzed by SDS PAGE electrophoresis test and Western blot assay. Results SDS PAGE analysis showed an induced expression product band of about 44 000,which constituted about 20% of the total bacterial proteins.His 6-rV+was purified in one step to 90% of purity from bacterial lysates.Western blot assay demonstrated that the His 6+rV+had good antigenicity. Conclusion His 6 fusion expression vector can effectively express and purify rV+protein.