双功能木聚糖酶Xyn2083的异源表达和酶学性质研究

The heterologous expression and characterization of a bifunctional xylanase Xyn2083

木聚糖酶Xyn2083来源于Clostridium clariflavum,是一种双功能木聚糖酶,包括2个催化结构域GH11、GH10(glycosyl hydrolase families,GH)和一个非催化结构域DockerinΙ。在文中,将该双功能木聚糖酶基因及GH11、GH10这2个结构域的木聚糖酶基因成功在大肠杆菌Rosetta (DE3)中进行异源表达,得到了3个重组木聚糖酶。将纯化后重组酶进行酶学性质分析,结果表明Xyn2083的最适反应温度与p H值分别为60℃、6. 0,且在60℃以下或p H 4. 5～10. 5的范围内有较好的稳定性。水解反应研究表明,Xyn2083中GH11和GH10结构域协同作用于木聚糖底物,将木聚糖水解为木糖和木二糖。

The Xyn2083 from Clostridium clariflavum was a bifunctional xylanase,which consisted of two xylanase catalytic domains(glycoside hydrolase family 11 and 10,GH11 and GH10)and one non-catalytic dockerinΙdomain.In this study,the bifunctional Xyn2083 and two truncated xylanases with GH11,GH10 domain organization were expressed as soluble proteins.The enzymatic properties of these recombinant xylanases were studied.The results showed that the optimal temperature and pH value of Xyn2083 were 60℃and 6.0,respectively.The Xyn2083 was stable below 60℃or at pH 4.5~10.5.The hydrolytic products analysis showed that the GH11 domain and GH10 domain in Xyn2083 had the functional cooperative action in hydrolysis of xylan into xylose and xylobiose.