title: Arabinoxylan degradation by fungi: characterization of the arabinoxylan-arabinofuranohydrolase encoding genes from Aspergillus niger and Aspergillus tubingensis.
abstract: The genes encoding the enzyme arabinoxylan arabinofuranohydrolase, which releases L-arabinose from arabinoxylan, have been cloned from the closely related fungi Aspergillus niger and Aspergillus tubingensis and were shown to be functional in A. niger. Integration of multiple copies in the genome resulted in over-expression of the enzymes. The arabinofuranohydrolases encoded comprise 332 amino acids and have 94% amino acid identity. Their primary structure is not related to those of other alpha-L-arabinofuranosidases, except for a low similarity with XYLC, a bacterial alpha-L-arabinofuranosidase from Pseudomonas fluorescens which acts on oat spelt xylan. The axhA expression pattern in A. niger differed from that of abfB, since it was strongly induced by birchwood xylan and much less by L-arabitol or L-arabinose. Furthermore, Northern analysis revealed that axhA expression was de repressed in creAd mutants and carbon catabolite repressed by D-glucose.
authors.affiliation: Section of Molecular Genetics of Industrial Microorganisms, Wageningen Agricultural University, Dreijenlaan 2, 6703 HA Wageningen, The Netherlands.
authors.forename: M M
authors.initials: MM
authors.lastname: Gielkens
authors.forename: J
authors.initials: J
authors.lastname: Visser
authors.forename: L H
authors.initials: LH
authors.lastname: de Graaff
mesh_terms: D000595:Amino Acid Sequence; D001089:Arabinose / Q000494:pharmacology; D001230:Aspergillus / Q000235:genetics*; D001234:Aspergillus niger / Q000235:genetics*; D015152:Blotting, Northern; D003001:Cloning, Molecular; D017931:DNA Primers / Q000235:genetics; D018076:DNA, Complementary / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial; D015971:Gene Expression Regulation, Enzymologic; D015966:Gene Expression Regulation, Fungal; D015723:Gene Library; D005947:Glucose / Q000494:pharmacology; D006026:Glycoside Hydrolases / Q000235:genetics* / Q000378:metabolism*; D008969:Molecular Sequence Data; D010957:Plasmids; D016133:Polymerase Chain Reaction; D011551:Pseudomonas fluorescens / Q000235:genetics; D015183:Restriction Mapping; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D013402:Sugar Alcohols / Q000494:pharmacology; D014990:Xylans / Q000378:metabolism* / Q000494:pharmacology
chemical_list: D017931:DNA Primers; D018076:DNA, Complementary; D013402:Sugar Alcohols; D014990:Xylans; C085118:arabinoxylan; D001089:Arabinose; D006026:Glycoside Hydrolases; C019713:alpha-N-arabinofuranosidase; D005947:Glucose; C014999:arabitol