期刊
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
卷 74, 期 -, 页码 263-270出版社
ELSEVIER SCIENCE BV
DOI: 10.1016/j.ijbiomac.2014.12.005
关键词
Aspergillus niger US368; Xylanase; Gene cloning; Expression; Escherichia coli BL21; Copper
资金
- Tunisian Ministry of Higher Education and Scientific Research and Technology [RL02CBS01]
The XAn11 cDNA was cloned in pET-28a(+) and the recombinant plasmid was transformed in Escherichia coli. The His-tagged r-XAn11 was purified using Ni-NTA affinity and anion exchange chromatography. The enzyme showed a specific activity of 415.1 U mg(-1) and a molecular mass of 25 kDa. It had an optimal activity at pH 5 and 50 degrees C. It was stable in a wide range of pH and in the presence of some detergents and organic solvents. In the presence of 3 mM Cu2+, the relative activity of the His-tagged r-XAn11 was enhanced by 54%. This is the first work reporting that copper is a strong activator for xylanase activity making this enzyme very attractive for future industrial applications. Molecular modeling suggests that the contact region between the catalytic site and the N-terminal His-tag fusion peptide could be responsible for the different behavior of the native and recombinant enzyme toward copper. (C) 2014 Elsevier B.V. All rights reserved.
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