木聚糖酶基因xynA在大肠杆菌中的表达研究

Expression of Xylanase Gene xynA in Escherichia coli

通过引物拼接的方式合成采用大肠杆菌优势密码子的疏棉状嗜热丝孢菌木聚糖酶基因xynA,插入到热激质粒pHsh和质粒pET-20b中构建重组质粒pHsh-xynA和pET-20b-xynA,再转入大肠杆菌JM109表达。经热激和IPTG诱导后,木聚糖酶在重组菌中获得特异性表达,产物以胞内可溶性蛋白和包涵体形式存在。重组菌pET-20b-xynA在16℃下表达量最大,胞内酶活达42.13 U/ml,重组菌pHsh-xynA在42℃下胞内酶活最大,为35.06 U/ml。与质粒pHsh相比,pET-20b质粒更有利于重组木聚糖酶的表达。

A codon-optimized xylanase gene（xynA） from Thermomyces lanuginosus was synthesized by primer splicing,and inserted into the expression vectors pHsh and pET-20b.The xynA gene was expressed in the recombinant vector pHsh-xynA（inducing with heat-shock） and pET-20b-xynA（inducing with IPTG）.The expression products existed as both soluble proteins and inclusion bodies.A maximum activity of 42.13 U/ml was obtained in pET-20b-xynA at 16 ℃.The expression level of recombinant xylanase in pHsh-xynA was lower,which reached to 35.06 U/ml.Compared to the vector pHsh,pET-20b was more effective for the recombinant xylanase expression.