The N-terminal cellulose-binding domain of EGXA increases thermal stability of xylanase and changes its specific activities on different substrates  

作　　者：Ming Ding Yigang Teng Qiuyu Yin Jie Zhao Fukun Zhao 

机构地区：[1]Key Laboratory of Proteomics, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 20031, China [2]College of Life Science, Zhejiang Sci-Tech University, Hangzhou 310018, China

出　　处：《Acta Biochimica et Biophysica Sinica》2008年第11期949-954,共6页生物化学与生物物理学报（英文版）

基　　金：This work was supported by grants from the National Natural Science Foundation of China （No. 30370336）, the Major State Basic Research Development Program of China （Nos. 2003CB716006 and 2004CB719702）, and the Creation Foundation from Shanghai Institutes for Biological Sciences

摘　　要：A full-length EGXA enzyme from a mollusk, Ampullaria crossean, was cloned into pFastBac vector and then heterogeneously expressed in insect Tn5 cells. Its natural N-terminal signal peptide worked well in the insect Tn5 cells. The recombinant EGXA was a 63 kDa protein and had active endo-β-1,4-glucanase （EC 3.2.1.4） and endo-β-1,4-xylanase （EC 3.2.1.8）. The specific activity of endo-β-1,4-xylanase was higher than in the EGX, which was purified from the stomach tissues of Ampullaria crossen. The N-terminal cellulose-binding domain of EGXA made it bind to cellulose and xylan more efficiently. This cellulose-binding domain also increased the thermal stability of this recombinant enzyme and decreased the recombinant EGXA＇s specific activities on β-nitrophenyl-β-D-cellobioside and sodium carboxymethyl cellulose.A full-length EGXA enzyme from a mollusk, Ampullaria crossean, was cloned into pFastBac vector and then heterogeneously expressed in insect Tn5 cells. Its natural N-terminal signal peptide worked well in the insect Tn5 cells. The recombinant EGXA was a 63 kDa protein and had active endo-β-1,4-glucanase （EC 3.2.1.4） and endo-β-1,4-xylanase （EC 3.2.1.8）. The specific activity of endo-β-1,4-xylanase was higher than in the EGX, which was purified from the stomach tissues of Ampullaria crossen. The N-terminal cellulose-binding domain of EGXA made it bind to cellulose and xylan more efficiently. This cellulose-binding domain also increased the thermal stability of this recombinant enzyme and decreased the recombinant EGXA＇s specific activities on β-nitrophenyl-β-D-cellobioside and sodium carboxymethyl cellulose.

关 键 词：endo-β- 1 4-glucanase endo-β-1 4-xylanase pNPCase CMCASE EGXA Ampullaria crossean cellulose-binding domain 

分 类 号：Q5[生物学—生物化学]