Intein介导的重组昆虫毒素BmK IT在大肠杆菌中的可溶性表达、纯化及活性分析

Soluble Expression，Purification and Characterization of BmK IT in Escherichia coli by Intein-mediated System

摘要:

为获得重组蝎昆虫毒素BmK IT，通过PCR方法在BmK IT基因的3′端融合了编码6个组氨酸残基的核苷酸序列，将其插入原核表达载体pTWIN1的内含肽 Ssp DnaB Intein基因下游的多克隆位点（MCS）。将获得的表达质粒转化大肠杆菌BL21（DE3）中，用IPTG诱导融合蛋白表达。用Ni-NTA亲和层析柱从菌体裂解液中纯化了CBD-Intein-BmK IT^his6融合蛋白，并在柱上诱导Intein自剪切，成功去除融合子CBD-Intein。通过Superdex 75凝胶过滤层析获得了纯度达95%以上的BmK IT^his6蛋白，该蛋白不仅具有正确的二级结构而且有生物活性。

Abstract:

To produce recombinant Buthus martensii Karsch insect toxin (BmK IT)，BmK IT cDNA which fused a hexahistidine sequence at the C-terminus by PCR was inserted into pTWIN1 expression vector fused in frame with an upstream Ssp DnaB intein gene. The expression plasmid was transformed into E. coli BL21 (DE3) strain and protein expression was induced by IPTG. The CBD-Intein-BmK IT^his6 fusion protein was purified from cell lysates using Ni-NTA resin affinity chromatography. The intein was removed from fusion protein by on-column intein-mediated cleavage. BmK IT^his6 was purified through Superdex 75 gel chromatography to more than 95% homogeneity. The purified protein has both correct secondary structure and insecticidal activity.