Genetic and biochemical characterization of a highly thermostable alpha-L-arabinofuranosidase from Thermobacillus xylanilyticus

The gene encoding an alpha-L-arabinofuranosidase from Thermobacillus xylani lyticus D3, AbfD3, was isolated. Characterization of the purified recombina nt alpha-L-arabinofuranosidase produced in Escherichia coli revealed that i t is highly stable with respect to both temperature (up to 90 degrees C) an d 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 g lycosyl hydrolase classification system. However, substrate specificity ana lysis revealed that AbfD3, unlike the majority of F51 members, displays hig h activity in the presence of polysaccharides.