甜蛋白monellin基因在酿酒酵母中的分泌表达

Secretory Expression of A Sweet Protein,Monellin,in Saccharomyces cerevisiae

人工合成的单链甜蛋白monellin基因与经改造后的基因分别克隆到带有酵母半乳糖可诱导启动子GAL1的穿梭表达质粒pYES2.0中,得到表达载体pYESM及pYESMT。在表达载体pYESMT中,monellin基因的上游连接酿酒酵母的α-信号肽序列,得到分泌表达载体pYESMTA。分别将3个重组质粒转化酿酒酵母菌株INVsc1中进行表达。具有突变monellin基因的菌株INVMT/pYESMT的monellin蛋白表达量明显高于含monellin基因的菌株。而含有pYESMTA的菌株可将monellin基因分泌到胞外,表明α-信号肽序列能很好地将酿酒酵母中的重组monellin蛋白引导到胞外,完成分泌表达,且表达产物具有生物活性。

The synthesized single-chain monellin gene was mutated. The gene and the original one were cloned into a E. coli -yeast shuttle vector pYES2.0 which carries the galaetose-indueible promoter GALl, resulting in the expression vectors pYESM and pYESMT. Meanwhile the α-factor signal peptide of S. cerevisiae was linked in pYESMT, resulting in the secretory expression vector pTESMTA. The recombinant plasmids were transformed into yeast. The expression level of monellin in pYESMT was higher than that in pYESM, and the strain containing pYESMTA plasmid could secret active monellin into the medium.