title: Enzyme system of Clostridium stercorarium for hydrolysis of arabinoxylan: reconstitution of the in vivo system from recombinant enzymes.
abstract: Four extracellular enzymes of the thermophilic bacterium Clostridium stercorarium are involved in the depolymerization of de-esterified arabinoxylan: Xyn11A, Xyn10C, Bxl3B, and Arf51B. They were identified in a collection of eight clones producing enzymes hydrolysing xylan (xynA, xynB, xynC), beta-xyloside (bxlA, bxlB, bglZ) and alpha-arabinofuranoside (arfA, arfB). The modular enzymes Xyn11A and Xyn10C represent the major xylanases in the culture supernatant of C. stercorarium. Both hydrolyse arabinoxylan in an endo-type mode, but differ in the pattern of the oligosaccharides produced. Of the glycosidases, Bxl3B degrades xylobiose and xylooligosaccharides to xylose, and Arf51B is able to release arabinose residues from de-esterified arabinoxylan and from the oligosaccharides generated. The other glycosidases either did not attack or only marginally attacked these oligosaccharides. Significantly more xylanase and xylosidase activity was produced during growth on xylose and xylan. This is believed to be the first time that, in a single thermophilic micro-organism, the complete set of enzymes (as well as the respective genes) to completely hydrolyse de-esterified arabinoxylan to its monomeric sugar constituents, xylose and arabinose, has been identified and the enzymes produced in vivo. The active enzyme system was reconstituted in vitro from recombinant enzymes.
authors.affiliation: Research Group Microbial Biotechnology, Technische Universität München, Am Hochanger 4, D-85350 Freising-Weihenstephan, Germany.
authors.forename: Helmuth
authors.initials: H
authors.lastname: Adelsberger
authors.affiliation: Research Group Microbial Biotechnology, Technische Universität München, Am Hochanger 4, D-85350 Freising-Weihenstephan, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Hertel
authors.affiliation: Research Group Microbial Biotechnology, Technische Universität München, Am Hochanger 4, D-85350 Freising-Weihenstephan, Germany.
authors.forename: Erich
authors.initials: E
authors.lastname: Glawischnig
authors.affiliation: Institute of Molecular Genetics, Russian Academy of Science, Kurchatov Square, 123182 Moscow, Russia.|Research Group Microbial Biotechnology, Technische Universität München, Am Hochanger 4, D-85350 Freising-Weihenstephan, Germany.
authors.forename: Vladimir V
authors.initials: VV
authors.lastname: Zverlov
authors.affiliation: Research Group Microbial Biotechnology, Technische Universität München, Am Hochanger 4, D-85350 Freising-Weihenstephan, Germany.
authors.forename: Wolfgang H
authors.initials: WH
authors.lastname: Schwarz
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D003013:Clostridium / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D003470:Culture Media; D015964:Gene Expression Regulation, Bacterial; D006026:Glycoside Hydrolases / Q000378:metabolism; D006868:Hydrolysis; D008969:Molecular Sequence Data; D011134:Polysaccharides / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism*; D013379:Substrate Specificity; D014990:Xylans / Q000378:metabolism*; D014995:Xylosidases / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D003470:Culture Media; D011134:Polysaccharides; D011994:Recombinant Proteins; D014990:Xylans; C007916:hemicellulose; C085118:arabinoxylan; D006026:Glycoside Hydrolases; D014995:Xylosidases