古菌Pyrococcus furiosus嗜热α-淀粉酶基因在酿酒酵母中的表达

EXPRESSION OF A HYPERTHERMOPHILIC α-AMYLASE OF THE ARCHAEON PYROCOCCUS FURIOSUS IN SACCHAROMYCES CEREVISIAE

用PCR方法从嗜热古菌Pyrococcusfuriosus的基因组DNA中扩增出胞外α 淀粉酶成熟肽结构基因 ,插入 pUC19中构建成质粒 pUC19 amy。将 pUC19 amy外源片段接入酿酒酵母表达载体 pYX2 12多克隆位点 ,构建成载体 pYX2 12 amy ,电转化酿酒酵母W 30 3 1A。转化子成功表达出有活性的高嗜热α 淀粉酶。重组酶具有与P furiosus产生的胞外α 淀粉酶相似的酶学性质 :最适 pH为 5 0 ,最适温度约为 90℃ ,在 12 1℃下热处理 30min酶活仍能保持 5 0

The structural gene encoding mature peptide of extracellular α amylase was amplified from the genome DNA of hyperthermophilic archaeon Pyrococcus furiosus by PCR The recombinant plasmid pUC19 amy was constructed by inserting the amplified segment into vector pUC19 The recombinant vector pYX212 amy was constructed by ligate the heterogeneous fragment of pUC19 amy into the multiple cloning site of pYX212, an expression vector of yeast Saccharomyces cerevisiae W303 A1 were transformed with pYX212 amy by electroporation The transformant expressed the activity of the thermophilic α amylase successfully The recombinant enzyme has the similar enzymatic properties as the extracellular α amylase produced by Pyrococcus furiosus : it shows an enzymatic activity optimum at pH 5 0, and its optimal temperature for enzymatic activity is about 90℃, more than 50% of its initial enzymatic activity is still detectable after it was incubated at 121℃ for 30 minutes