人趋化因子受体CCR5胞外片段的融合表达与纯化

目的 对人趋化因子受体CCR5的N端胞外部分与第二个胞外环(extracellular loop-2,ECL-2)进行融合表达与纯化.方法 分别扩增人趋化因子受体CCR5的胞外N.端部分与ECL-2部分相应的编码序列,通过重叠延伸拼接(splicing byoverlapping extension,SOE)PCR实现两片段DNA的拼接后(命名为CCR5-N-E2)克隆人质粒pBlueScript M13中,同时构建原核表达载体pET-21b(+)-CCR5-N-E2,转入表达菌株BL21(DE3),IVIG诱导表达重组蛋白CCR5-N-E2,表达产物通过蛋白免疫印迹进行鉴定,并采用金属螯合层析法对重组表达产物进行纯化.结果 经测序,构建的重组原核表达载体与预期完全一致,相对分子质量为8 500的日的蛋白在BL21(DE3)菌株中得到高效表达,表达量约占总蛋白的50%,表达产物以包涵体形式存在.蛋白免疫印迹实验表明该重组蛋白与抗CCR5 N.端序列的单克隆抗体发生特异性结合.通过Ni2+亲和层析,目的 蛋白的纯度可达95%以上.结论 实现CCR5-N-E2编码序列的拼接、融合蛋白的表达以及纯化,为广泛筛选以CCR5为靶点的临床治疗药物奠定了基础.

Expression and purification of the extracellular domains of human chemokine receptor CCR5

Objective To express and purify the first extracellular domain and extracellular loop 2(ECL-2) of human chemokine receptor CCR5.Methods Gene fragments of the first extracellular domain and ECL-2 were amplified respectively and then spliced by Splicing of overlapping extension(SOE) PCR.This fragment was inserted into the prokaryotic expression vector pET-21b(+) and transformed into E.coli strain BL21(DE3),and then inducted with IPTG.The recombinant protein fusing with 6His-tag,named CCR5-N-E2,was detected by...