应用硫氧还蛋白促进外源蛋白在大肠杆菌的可溶性表达

CO-EXPRESSION OF THIOREDOXIN INCREASED THE SOLUBILITY OF FOREIGN PROTEIN EXPRESSED IN E.COLI

为了观察硫氧还蛋白（ＴｒｘＡ）促进外源蛋白在大肠杆菌中可溶性表达的作用，我们从质粒ｐＥＴ－３２ａ（＋）上克隆了ｔｒｘＡ基因，构建了ＴｒｘＡ表达质粒ｐＴ－ＴｒｘＡ。将该质粒与其它蛋白基因的表达质粒共同转化Ｅｃｏｌｉ并同时获得表达。结果表明，共表达ＴｒｘＡ可以明显促进外源蛋白，如甲状旁腺激素相关蛋白（ＰＴＨｒＰ）、ＰＴＨｒＰ受体（ＰＴＨｒＰ－Ｒ）和血管内皮生长因子（ＶＥＧＦ）的可溶性表达。说明共表达ＴｒｘＡ有助于外源蛋白的正确折叠，防止包涵体的形成。

Expression vector with Chloramphenicol resistant gene containing E. coli thioredoxin (trxA) gene downstream of T7 promoter was constructed and transformed into E. coli strain BL21.Then pET-3a vectors encoding various foreign proteins, including PTHrP (Parathyroid hormone related protein)、 PTHrP receptor and VEGF (Vascular endothelial growth factor, VEGF) were co-transformed into the above strain. These bacteria could produce both the foreign protein and TrxA. The results of SDS-PAGE demonstrated that the coproduction of TrxA can promote the soluble expression of foreign proteins.