Nucleotide sequence of the Clostridium stercorarium xylA gene encoding a bifunctional protein with beta-D-xylosidase and alpha-L-arabinofuranosidase activities, and properties of the translated product.
The nucleotides of the beta-xylosidase (xylA) gene from Clostridium stercorarium were sequenced. A single open reading frame of 473 codons specifying the subunit (MW 53,340) of xylosidase was identified. The N-terminal amino acid sequence and molecular weight estimated by SDS-polyacrylamide gel electrophoresis of the purified enzyme were quite in agreement with those deduced from the nucleotide sequence. Analysis of the enzyme by gel filtration on an HPLC column gave a molecular weight of 220,000, suggesting that the native enzyme is a tetramer composed of 4 identical subunits. The pH optimum was 7.0 and quite stable over the pH range of 5 to 10 at 4 degrees C. The optimum temperature was 65 degrees C. Vm was estimated to be 5.9 nmol/min/micrograms for p-nitrophenyl-beta-D-xylopyranoside and 16.7 nmol/min/micrograms for p-nitrophenyl-alpha-L-arabinofuranoside, while Km was estimated to be 2.5 mM for p-nitrophenyl-beta-D-xylopyranoside and 17.6 mM for p-nitrophenyl-alpha-L-arabinofuranoside.
Sakka
K
K
Department of Bioscience, Faculty of Bioresources, Mie University, Tsu, Japan.
Yoshikawa
K
K
Kojima
Y
Y
Karita
S
S
Ohmiya
K
K
Shimada
K
K
D000595:Amino Acid Sequence; D001483:Base Sequence; D002851:Chromatography, High Pressure Liquid; D003001:Cloning, Molecular; D003013:Clostridium / Q000201:enzymology / Q000235:genetics*; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000235:genetics; D005798:Genes, Bacterial; D006026:Glycoside Hydrolases / Q000235:genetics* / Q000302:isolation & purification; D006863:Hydrogen-Ion Concentration; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010957:Plasmids; D014176:Protein Biosynthesis / Q000235:genetics; D013696:Temperature; D014995:Xylosidases / Q000235:genetics* / Q000302:isolation & purification
D006026:Glycoside Hydrolases; D014995:Xylosidases; C026579:exo-1,4-beta-D-xylosidase; C019713:alpha-N-arabinofuranosidase