Abstract
The nucleotides of the xynB gene of Clostridium stercorarium F-9 were sequenced. The structural gene consists of an open reading frame of 1161 bp encoding a xylanase (XynB) in family F of 387 amino acids with a molecular weight of 44,377. The molecular weight of the enzyme purified from a recombinant Escherichia coli was around 41,000, smaller than the predicted value, on SDS-polyacrylamide gel electrophoresis due to the lack of 32 amino acids at the N-terminus. Intact XynB with a molecular weight of around 43,000 was immunologically detected in the total cell proteins of a recombinant E. coli and C. stercorarium F-9. The purified XynB was active toward xylan, carboxymethylcellulose, p-nitrophenyl-beta-D-xylopyranoside and p-nitrophenyl-beta-D-cellobioside. The pH optimum was 7.0 and it was quite stable over the pH range of 5 to 12 at 4 degrees C. This enzyme was optimally active at 80 degrees C and retained about 50% of the original activity even after incubation at 100 degrees C for 10 min.
Publication types
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Comparative Study
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence
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Base Sequence
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Clostridium / enzymology
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Clostridium / genetics*
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Electrophoresis, Polyacrylamide Gel
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Enzyme Stability
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Escherichia coli / enzymology*
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Escherichia coli / genetics
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Gene Expression Regulation, Enzymologic / genetics
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Glucosides / chemistry
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Glycoside Hydrolases / chemistry
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Glycosides / chemistry
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Hot Temperature
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Hydrogen-Ion Concentration
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Molecular Sequence Data
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Molecular Weight
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Nitrophenylgalactosides / chemistry
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Promoter Regions, Genetic
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Protein Biosynthesis / genetics
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Restriction Mapping
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Sequence Homology, Amino Acid
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Sequence Homology, Nucleic Acid
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Substrate Specificity
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Xylan Endo-1,3-beta-Xylosidase
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Xylosidases / chemistry
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Xylosidases / genetics*
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Xylosidases / isolation & purification
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Xylosidases / metabolism
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beta-Glucosidase / chemistry
Substances
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Glucosides
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Glycosides
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4-nitrophenyl beta-D-xyloside
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Nitrophenylgalactosides
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4-nitrophenylgalactoside
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4-nitrophenyl beta-cellobioside
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Glycoside Hydrolases
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Xylosidases
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cellobiosidase
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beta-Glucosidase
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Xylan Endo-1,3-beta-Xylosidase
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exo-1,4-beta-D-xylosidase