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Improvement in thermostability of metagenomic GH11 endoxylanase (Mxyl) by site-directed mutagenesis and its applicability in paper pulp bleaching process
- Source :
- Journal of Industrial Microbiology and Biotechnology. 40:1373-1381
- Publication Year :
- 2013
- Publisher :
- Oxford University Press (OUP), 2013.
-
Abstract
- An attempt has been made for enhancing the thermostability of xylanase (Mxyl) retrieved from a compost-soil-based metagenomic library. The analysis of the structure of xylanase by molecular dynamics simulation revealed more structural fluctuations in β-sheets. When the surface of β-sheets was enriched with arginine residues by substituting serine/threonine by site-directed mutagenesis, the enzyme with four arginine substitutions (MxylM4) exhibited enhanced thermostability at 80 °C. The T 1/2 of MxylM4 at 80 °C, in the presence of birchwood xylan, increased from 130 to 150 min at 80 °C without any alteration in optimum pH and temperature and molecular mass. Improvement in thermostability of MxylM4 was corroborated by increase in T m by 6 °C over that of Mxyl. The K m of MxylM4, however, increased from 8.01 ± 0.56 of Mxyl to 12.5 ± 0.32 mg ml−1, suggesting a decrease in the affinity as well as specific enzyme activity. The Mxyl as well as MxylM4 liberated chromophores and lignin-derived compounds from kraft pulp, indicating their applicability in pulp bleaching.
- Subjects :
- Paper
Arginine
Molecular Sequence Data
Bioengineering
Molecular Dynamics Simulation
Applied Microbiology and Biotechnology
Catalysis
Industrial Microbiology
Enzyme Stability
Escherichia coli
Amino Acid Sequence
Threonine
Site-directed mutagenesis
Thermostability
Endo-1,4-beta Xylanases
Molecular mass
Chemistry
Mutagenesis
Temperature
Recombinant Proteins
Protein Structure, Tertiary
Kinetics
Amino Acid Substitution
Kraft process
Biochemistry
Mutagenesis, Site-Directed
Xylanase
Metagenomics
Biotechnology
Subjects
Details
- ISSN :
- 14765535 and 13675435
- Volume :
- 40
- Database :
- OpenAIRE
- Journal :
- Journal of Industrial Microbiology and Biotechnology
- Accession number :
- edsair.doi.dedup.....13d95d487e6fe541c7f53eac92f748d0