地衣芽孢杆菌普鲁兰酶编码基因的鉴定

Identification of a gene encoding pullulanase from Bacillus licheniformis

对地衣芽孢杆菌基因组序列分析显示,其中标注为amyX的基因可能编码普鲁兰酶。以PCR方法,从地衣芽孢杆菌染色体DNA中扩增出amyX基因蛋白编码区,插入大肠杆菌表达载体pET28 a T7启动子下游。含重组质粒的大肠杆菌BL21(DE3)在IPTG诱导下表达出有活性的普鲁兰酶。酶学性质初步分析表明,重组普鲁兰酶最适反应温度为40℃,最适pH值为6.0。

Analysis of the complete genome sequence of Bacillus licheniformis revealed a putative pullulanase gene annotated as amyX. The coding region of amyX gene was amplified from genome DNA of B. licheniformis by PCR and inserted into the downstream of T7 promoter of the expression vector pET28a. The recombinant plasmid was transformed into the Escherichia coli BL21 （DE3）. Induced with IPTG the recombinant E. coli expressed the pullulanase active. The recombinant enzyme activity showed optimal pH and temperature were 6. 0 and about 40℃, respectively.