Genetic and Biochemical Characterization of a Highly Thermostable α-l-Arabinofuranosidase from Thermobacillus xylanilyticus

The gene encoding an α-l-arabinofuranosidase from Thermobacillus xylanilyticus D3, AbfD3, was isolated. Characterization of the purified recombinant α-l-arabinofuranosidase produced in Escherichia coli revealed that it is highly stable with respect to both temperature (up to 90°C) and pH (stable in the pH range 4 to 12). On the basis of amino acid sequence similarities, this 56,071-Da enzyme could be assigned to family 51 of the glycosyl hydrolase classification system. However, substrate specificity analysis revealed that AbfD3, unlike the majority of F51 members, displays high activity in the presence of polysaccharides.