InterPro domain: IPR044993

This entry represents a group of beta-D-xylosidases mainly from bacteria, fungi, animals and plants. They belong to a subgroup of the glycoside hydrolase family 3.

Xylan, a prominent component of cellulosic biomass, has a high potential for degradation into reducing sugars, and subsequent conversion into bioethanol. This process requires a range of xylanolytic enzymes, including beta-xylosidases. This entry includes fungal exo-1,4-beta-xylosidase xlnD [ 1 , 2 ] and bxlB [ 3 ].

In bacteria, Prevotella ruminicola Xyl3A has been shown to have beta-xylosidase activity via its capacity to hydrolyze glycosidic linkages of beta-1,4-xylo-oligosaccharides of various lengths (X2 to X6), releasing xylose monomers [ 4 ].

In Arabidopsis, there are seven members AtBXL1-7 in this entry. AtBXL1 is a bifunctional beta-d-xylosidase/alpha-l-arabinofuranosidase required for pectic arabinan modification and is involved in secondary cell wall metabolism and plant development [ 5 , 6 , 7 ].

1. β-Xylosidases: Structural Diversity, Catalytic Mechanism, and Inhibition by Monosaccharides. Int J Mol Sci 20, 57-68
2. Heterologous expression of Aspergillus niger beta-D-xylosidase (XlnD): characterization on lignocellulosic substrates. Appl Biochem Biotechnol 146, 3328-38
3. Development and application of a suite of polysaccharide-degrading enzymes for analyzing plant cell walls. Proc. Natl. Acad. Sci. U.S.A. 103, 11417-22
4. Biochemical analysis of a beta-D-xylosidase and a bifunctional xylanase-ferulic acid esterase from a xylanolytic gene cluster in Prevotella ruminicola 23. J Bacteriol 191, 1219-34
5. AtBXL1 encodes a bifunctional beta-D-xylosidase/alpha-L-arabinofuranosidase required for pectic arabinan modification in Arabidopsis mucilage secretory cells. Plant Physiol 150, 677-90
6. AtBXL1, a novel higher plant (Arabidopsis thaliana) putative beta-xylosidase gene, is involved in secondary cell wall metabolism and plant development. Plant J 33, 867-78
7. Purification and characterization of enzymes exhibiting beta-D-xylosidase activities in stem tissues of Arabidopsis. Plant Physiol 135, 2339-51