A novel GH43 alpha-L-arabinofuranosidase from Humicola insolens: mode of action and synergy with GH51 alpha-L-arabinofuranosidases on wheat arabinoxylan

Appl Microbiol Biotechnol. 2006 Dec;73(4):850-61. doi: 10.1007/s00253-006-0543-y. Epub 2006 Aug 30.


A novel alpha-L-arabinofuranosidase (alpha-AraF) belonging to glycoside hydrolase (GH) family 43 was cloned from Humicola insolens and expressed in Aspergillus oryzae. (1)H-NMR analysis revealed that the novel GH43 enzyme selectively hydrolysed (1-->3)-alpha-L-arabinofuranosyl residues of doubly substituted xylopyranosyl residues in arabinoxylan and in arabinoxylan-derived oligosaccharides. The optimal activity of the cloned enzyme was at pH 6.7 and 53 degrees C. Two other novel alpha-L-arabinofuranosidases (alpha-AraFs), both belonging to GH family 51, were cloned from H. insolens and from the white-rot basidiomycete Meripilus giganteus. Both GH51 enzymes catalysed removal of (1-->2) and (1-->3)-alpha-L-arabinofuranosyl residues from singly substituted xylopyranosyls in arabinoxylan; the highest arabinose yields were obtained with the M. giganteus enzyme. Combinations (50:50) of the GH43 alpha-AraF from H. insolens and the GH51 alpha-AraFs from either M. giganteus or H. insolens resulted in a synergistic increase in arabinose release from water-soluble wheat arabinoxylan in extended reactions at pH 6 and 40 degrees C. This synergistic interaction between GH43 and GH51 alpha-AraFs was also evident when a GH43 alpha-AraF from a Bifidobacterium sp. was supplemented in combination with either of the GH51 enzymes. The synergistic effect is presumed to be a result of the GH51 alpha-AraFs being able to catalyse the removal of single-sitting (1-->2)-alpha-L- arabinofuranosyls that resulted after the GH43 enzyme had catalysed the removal of (1-->3)-alpha-L-arabinofuranosyl residues on doubly substituted xylopyranosyls in the wheat arabinoxylan.

MeSH terms

  • Amino Acid Sequence
  • Arabinose / metabolism
  • Ascomycota / enzymology*
  • Ascomycota / genetics
  • Aspergillus oryzae / genetics
  • Bifidobacterium / enzymology
  • Cloning, Molecular
  • Enzyme Stability
  • Gene Expression
  • Glycoside Hydrolases / genetics
  • Glycoside Hydrolases / isolation & purification*
  • Glycoside Hydrolases / metabolism*
  • Hydrogen-Ion Concentration
  • Magnetic Resonance Spectroscopy
  • Molecular Sequence Data
  • Oligosaccharides / metabolism
  • Polyporales / enzymology
  • Polyporales / genetics
  • Sequence Alignment
  • Substrate Specificity
  • Temperature
  • Triticum
  • Xylans / metabolism*


  • Oligosaccharides
  • Xylans
  • arabinoxylan
  • Arabinose
  • Glycoside Hydrolases
  • alpha-N-arabinofuranosidase