Nucleotide Sequence of the Clostridium stercorarium xynB Gene Encoding an Extremely Thermostable Xylanase, and Characterization of the Translated Product

概要

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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-β-D-xylopyranoside and p-nitrophenyl-β-D-cellobioside. The pH optimum was 7.0 and it was quite stable over the pH range of 5 to 12 at 4℃. This enzyme was optimally active at 80℃ and retained about 50% of the original activity even after incubation at 100℃ for 10 min.
社団法人日本農芸化学会の論文
1995-01-23