Partial characterization of structure and function of a xylanase gene from the rumen hemicellulolytic bacterium Eubacterium ruminantium

Hidenori Taguchi, Satoshi Koike, Yasuo Kobayashi, Isaac K.O. Cann, Shuichi Karita

Research output: Contribution to journalArticle

Abstract

A gene encoding for xylanase activity in the rumen hemicellulolytic bacterium Eubacterium ruminantium was cloned into pBR322 in Escherichia coli (E. coli). The primary clone had a 5.7 kb insert produced by Eco RI partial digestion. Subcloning followed by sequencing allowed for the discovery that this enzyme has a glycosyl-hydrolase family 10 catalytic domain with a family 9 carbohydrate binding module at C-terminus and a region partially homologous to a family 22 carbohydrate binding module at N-terminus. Cloned xylanase is specifically active against xylan and oligoxyloside to produce xylobiose and xylotriose, showing optimal pH and temperature at 7.0 and 50°C, respectively. Molecular size of the xylanase (91 kDa) was confirmed by zymogram analysis of the E. coli clone, which agreed with the predicted size from the DNA sequence. Functions of the two modules at C- and N-termini were evaluated by using xylanase variants with and without the respective module and the C-terminal module was found to be functional in binding to acid-swollen cellulose and insoluble oat-spelt xylan, whereas the N-terminal module was inactive for binding them.

Original languageEnglish (US)
Pages (from-to)325-332
Number of pages8
JournalAnimal Science Journal
Volume75
Issue number4
DOIs
StatePublished - Aug 1 2004

Keywords

  • Carbohydrate binding module
  • Enzyme activity
  • Eubacterium ruminantium
  • Rumen bacterium
  • Xylanase gene

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)

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