title: Cloning, sequencing and expression of a gene encoding a 73 kDa xylanase enzyme from the rumen anaerobe Butyrivibrio fibrisolvens H17c.
abstract: The cloning, expression and nucleotide sequence of a 3 kb DNA segment on pLS206 containing a xylanase gene (xynB) from Butyrivibrio fibrisolvens H17c was investigated. The open reading frame (ORF) of 1905 bp encoded a xylanase of 635 amino acid residues (Mr 73156). At least 850 bp at the 3' end of the gene could be deleted without loss of xylanase activity. The deduced amino acid sequence was confirmed by purifying the enzyme and subjecting it to N-terminal amino acid sequence analysis. In Escherichia coli C600 (pLS206) cells the xylanase was localized in the cytoplasm. Its optimum pH for activity was between pH 5.4 and 6, and optimum temperature 55 degrees C. The primary structure of the xylanase showed a significant level of identity with a cellobiohydrolase/endoglucanase of Caldocellum saccharolyticum, as well as with the xylanases of the alkaliphilic Bacillus sp. strain C-125, B. fibrisolvens strain 49, and Pseudomonas fluorescens subsp. cellulosa.
authors.affiliation: Department of Microbiology, University of Cape Town, Rondebosch, South Africa.
authors.forename: L L
authors.initials: LL
authors.lastname: Lin
authors.forename: J A
authors.initials: JA
authors.lastname: Thomson
mesh_terms: D000595:Amino Acid Sequence; D001438:Bacteroidaceae / Q000235:genetics*; D001483:Base Sequence; D003001:Cloning, Molecular; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000235:genetics; D015870:Gene Expression; D005798:Genes, Bacterial; D005960:Glucosides / Q000096:biosynthesis; D006026:Glycoside Hydrolases / Q000096:biosynthesis / Q000235:genetics* / Q000302:isolation & purification; D008969:Molecular Sequence Data; D016366:Open Reading Frames / Q000235:genetics; D010957:Plasmids; D015183:Restriction Mapping; D012689:Sequence Homology, Nucleic Acid; D043325:Xylan Endo-1,3-beta-Xylosidase; D001616:beta-Galactosidase / Q000096:biosynthesis; D001618:beta-Lactamases / Q000096:biosynthesis
chemical_list: D005960:Glucosides; C034170:4-nitrophenyl beta-cellobioside; D006026:Glycoside Hydrolases; D001616:beta-Galactosidase; D043325:Xylan Endo-1,3-beta-Xylosidase; D001618:beta-Lactamases