The abfB gene encoding the major α-L-arabinofuranosidase of Aspergillus nidulans: nucleotide sequence, regulation and construction of a disrupted strain Free

Abstract

Using a DNA fragment containing the gene as a probe, the homologous gene, designated has been cloned from a genomic library containing size-selected fragments. The nucleotide sequence of the gene shows strong homology with the and α-L-arabinofuranosidase/β-xylosidase genes. Regulation of expression has been investigated in cultures induced with L-arabitol. The accumulation of mRNA, total α-L-arabinofuranosidase activity and AbfB protein levels have been determined in a wild-type strain as well as in different mutant strains. These strains are affected either in their response to ambient pH ( and mutants), carbon catabolite repression ( mutant), the ability to utilize L-arabitol as a carbon source ( mutant) or a combination of both latter genotypes (). The results obtained indicate that the expression of the gene was higher at acidic pHs and was superinduced in this double mutant. Furthermore, disruption of the gene demonstrated that in AbfB is the major -nitrophenyl α-L-arabinofuranoside-hydrolysing activity but at least one minor activity is expressed, which is involved in the release of L-arabinose from polysaccharides.

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/content/journal/micro/10.1099/13500872-145-3-735
1999-03-01
2024-03-29
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