乳糖诱导甜蛋白Monellin在大肠杆菌中的表达

Expression of Plant Monellin in Escherichia coli Induced by Lactose

根据已报道的单链Monellin甜蛋白的氨基酸序列,按大肠杆菌基因偏爱密码子,设计和人工合成了单链monellin基因。将单链monellin基因克隆到大肠杆菌表达载体pET-28a中,构建了重组表达载体pET28a-mon,转化大肠杆菌BL21(DE3),得到表达Monellin的大肠杆菌工程菌株。借助SDS-PAGE分析方法,研究了乳糖代替IPTG诱导大肠杆菌表达甜蛋白Monellin。通过对乳糖作为诱导剂表达条件进行优化,Monellin的表达量可占细胞总蛋白的33.09%,与IPTG诱导表达量接近。为乳糖作为诱导剂应用于重组大肠杆菌生产甜蛋白Monellin提供了参考依据。

According to the amino acid sequence of Monellin and the bias in coden choice in Escheria coli, a single chain monellin gene was synthesized and subcloned into a Escheria coli expression vector pET-28a. The recombined plasmid pET28a-mon was then transformed into Escheria coli BI21 （ DE3 ）. Lactose was used as an inducer instead of IPTG. Through proper optimization of induction conditions, an expression level 33.09% of total cellular protein was achieved. The expression level of recombinant protein induced by lactose was basically the same as that induced by IPTG. The result indicated that lactose could be used as a promising inducer in the production of recombined sweet protein Monellin.