title: Two cellobiohydrolase-encoding genes from Aspergillus niger require D-xylose and the xylanolytic transcriptional activator XlnR for their expression.
abstract: Two cellobiohydrolase-encoding genes, cbhA and cbhB, have been isolated from the filamentous fungus Aspergillus niger. The deduced amino acid sequence shows that CbhB has a modular structure consisting of a fungus-type cellulose-binding domain (CBD) and a catalytic domain separated by a Pro/Ser/Thr-rich linker peptide. CbhA consists only of a catalytic domain and lacks a CBD and linker peptide. Both proteins are homologous to fungal cellobiohydrolases in family 7 of the glycosyl hydrolases. Northern blot analysis showed that the transcription of the cbhA and cbhB genes is induced by D-xylose but not by sophorose and, in addition, requires the xylanolytic transcriptional activator XlnR.
authors.affiliation: Section Molecular Genetics of Industrial Microorganisms, Wageningen Agricultural University, NL-6703 HA Wageningen, The Netherlands.
authors.forename: M M
authors.initials: MM
authors.lastname: Gielkens
authors.forename: E
authors.initials: E
authors.lastname: Dekkers
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; D001234:Aspergillus niger / Q000235:genetics*; D001665:Binding Sites; D002480:Cellulase / Q000737:chemistry / Q000235:genetics*; D002482:Cellulose / Q000378:metabolism; D043366:Cellulose 1,4-beta-Cellobiosidase; D003001:Cloning, Molecular; D005656:Fungal Proteins; D005800:Genes, Fungal; D008969:Molecular Sequence Data; D016415:Sequence Alignment; D015534:Trans-Activators / Q000502:physiology*; D014994:Xylose / Q000494:pharmacology*
chemical_list: D005656:Fungal Proteins; D015534:Trans-Activators; C115443:XlnR protein, Aspergillus; D002482:Cellulose; D014994:Xylose; D002480:Cellulase; D043366:Cellulose 1,4-beta-Cellobiosidase