The N-terminal cellulose-binding domain of EGXA increases thermal stability of xylanase and changes its specific activities on different substrates.
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-beta-1,4-glucanase (EC 3.2.1.4) and endo-beta-1,4-xylanase (EC 3.2.1.8). The specific activity of endo-beta-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 p-nitrophenyl-beta-D-cellobioside and sodium carboxymethyl cellulose.
Ding
Ming
M
Key Laboratory of Proteomics, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 20031, China.
Teng
Yigang
Y
Yin
Qiuyu
Q
Zhao
Jie
J
Zhao
Fukun
F
D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002482:Cellulose / Q000378:metabolism*; D017931:DNA Primers; D004795:Enzyme Stability; D008974:Mollusca; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D013379:Substrate Specificity; D013696:Temperature; D014995:Xylosidases / Q000737:chemistry / Q000378:metabolism*
D017931:DNA Primers; D011994:Recombinant Proteins; D002482:Cellulose; D014995:Xylosidases