嗜热脂肪土芽孢杆菌木聚糖酶基因的合成及其在大肠杆菌中的表达

来自嗜热脂肪土芽孢杆菌的木聚糖内切酶XT6在工业上有着重要的应用,已经成功应用于工业规模的生产试验.本文作者在合成XT6基因全序列的同时对其密码子进行了优化,且构建重组质粒在大肠杆菌中高表达.通过优化表达条件,功能正常的XT6基因在大肠杆菌中成功过量表达,蛋白表达量占细胞中总蛋白的65%.重组表达的木聚糖内切酶XT6特性和天然酶相似,以桦木木聚糖为底物测定细胞提取物中木聚糖酶活性,最大活性高达3 030 U/mL.本文首次报道了来自嗜热脂肪土芽孢杆菌中木聚糖酶基因全序列的合成和在大肠杆菌中成功过量表达.图6表1参19

De novo Synthesis and Expression of a Thermostable Xylanase from Geobacillus stearothermophilus in Escherichia coil

The endoxylanase XT6 secreted from Geobacillus stearothermophilus is a particularly attractive candidate for some industrial purposes and was used successfully on an industrial-scale mill trial. The gene was de novo synthesized with the codons adjusted to fit the bias of that of Escherichia coli and constructed into vector pET28a (+). After optimizing the expression conditions, functional xylanase XT6 was over expressed in E. coll with up to 65% of total protein. A maximum xylanase activity of 3,030 U/mL was obtained from cell extract against birchwood xylan. The recombinant XT6 was partly characterized and was similar with those of the native enzyme in G. stearothermophilus. This is the first report on the over expression of a de novo synthesized xylanase XT6 gene from Geobacillus stearothermophilus. Fig 6, Tab 1, Ref 19