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Publication Abstract from PubMed

Xylose, a key constituent of the heterogeneous hemicellulose polymer, occurs in lignocellulosic biomass and forms xylan polymers through beta-1,4 glycosidic linkages. The beta-1,4-xylosidase enzyme was isolated from Pseudopedobacter saltans (PsGH43) to find an effective enzyme with enhanced activity to depolymerize xylo-oligosaccharides. beta-1,4-xylosidase belongs to the GH43(1) family as classified in the Carbohydrate-Active Enzyme Database (CAZy). PsGH43(2) was found to be active only on xylose-based substrate, 4NPX(3), with maximum activity occurring at a pH 7 and 30 degrees C (K(m) 1.96 +/- 0.2 mM and V(max) 0.43 mM/min). The study also confirms the influence of Ca(2+) ions on enzymatic activity and thermal stability. Subsequently, native PsGH43 was crystallized at optimum conditions and the structure was determined at 2.5 A resolution. Crystallographic analysis revealed an asymmetric unit containing eight monomers and 16 calcium ions wherein a tetramer constituted the functional unit. Each monomer exhibits a characteristic GH43 N-terminal beta-propeller fold that serves as a catalytic domain accommodating one calcium ion in the centre, while the C-terminal beta-sandwich fold associated with the CBM6(4) family preserves another calcium ion. Our study reveals a novel tetrameric arrangement of beta-1,4-xylosidase which unravels its functional indispensability. This study opens newer avenues to engineer a potential enzyme for biofuel and bioethanol industry.

Deciphering the structural and biochemical aspects of xylosidase from Pseudopedobacter saltans.,Vishwakarma P, Sachdeva E, Thakur A, Ethayathulla AS, Goyal A, Kaur P Int J Biol Macromol. 2024 Dec 19;291:139042. doi: 10.1016/j.ijbiomac.2024.139042. PMID:39708861^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.