Debranching of arabinoxylan: properties of the thermoactive recombinant alpha-L-arabinofuranosidase from Clostridium stercorarium (ArfB).
The gene arfB encoding alpha-L-arabinofuranosidase B of the cellulolytic thermophile Clostridium stercorarium was expressed in Escherichia coli from a 2.2-kb EcoRI DNA fragment. The recombinant gene product ArfB was purified by fast-performance liquid chromatography. It has a tetrameric structure with a monomeric relative molecular mass of 5200. The optima for temperature and pH are 70 degrees C and 5.0 respectively. The enzyme appears to have no metal cofactor requirement and is sensitive to sulfhydryl reagents. It hydrolyzes aryl and alkyl alpha-L-arabinofuranosides and cleaves arabinosyl side-chains from arabinoxylan (oat-spelt xylan) and from xylooligosaccharides produced by recombinant endoxylanase XynA from the same organism. The identify of the N-terminal amino acid sequences indicates that ArfB corresponds to the major alpha-arabinosidase activity present in the culture supernatant of C. stercorarium.
Schwarz
W H
WH
Institut für Mikrobiologie, Technische Universität München, Germany.
Bronnenmeier
K
K
Krause
B
B
Lottspeich
F
F
Staudenbauer
W L
WL
D000595:Amino Acid Sequence; D003013:Clostridium / Q000201:enzymology*; D043364:Endo-1,4-beta Xylanases; D004926:Escherichia coli / Q000235:genetics; D006026:Glycoside Hydrolases / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D008969:Molecular Sequence Data; D008970:Molecular Weight; D011994:Recombinant Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D013379:Substrate Specificity; D013696:Temperature; D014990:Xylans / Q000378:metabolism*; D014995:Xylosidases
D011994:Recombinant Proteins; D014990:Xylans; C085118:arabinoxylan; D006026:Glycoside Hydrolases; D014995:Xylosidases; C019713:alpha-N-arabinofuranosidase; D043364:Endo-1,4-beta Xylanases