title: Sequencing and expression of the gene encoding the Clostridium stercorarium beta-xylosidase Xyl43B in Escherichia coli.
abstract: The Clostridium stercorarium F-9 xyl43B gene encoding the beta-xylosidase Xyl43B consists of an open reading frame of 1,491 nucleotides that encodes a putative protein, classified in family 43, of 497 amino acids with a predicted molecular weight of 56,355. The deduced amino acid sequence of Xyl43B has sequence similarity with beta-xylosidases from Bacteriodes thetaiotaomicron (57% sequence identity), Prevotella ruminicola (45%), Streptomyces coelicolor (40%), and Clostridium acetobutylicum (36%), all of which have been classified in family 43 of the glycoside hydrolases. Xyl43B was purified from a recombinant Escherichia coli and characterized. The optimum pH of the purified enzyme was 3.5 and it was stable over pH from 3.0 to 8.0. Its optimum temperature was 80 degrees C and it showed thermostability in the temperature range from 50 to 70 degrees C. Xyl43B had a K(m) of 6.2 mM and a V(max) of 15 micromol min(-1) mg(-1) for p-nitrophenyl-beta-D-xylopyranoside.
authors.affiliation: Faculty of Bioresources, Mie University, Tsu, Japan.
authors.lastname: Suryani
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Kimura
authors.forename: Kazuo
authors.initials: K
authors.lastname: Sakka
authors.forename: Kunio
authors.initials: K
authors.lastname: Ohmiya
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D003013:Clostridium / Q000201:enzymology* / Q000235:genetics; D004795:Enzyme Stability; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics; D015870:Gene Expression; D006863:Hydrogen-Ion Concentration; D008969:Molecular Sequence Data; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D013696:Temperature; D014995:Xylosidases / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D014995:Xylosidases; C026579:exo-1,4-beta-D-xylosidase