Structural Characterization of β-Xylosidase XynB2 from Geobacillus stearothermophilus CECT43: A Member of the Glycoside Hydrolase Family GH52 Gavira Gallardo, José Antonio Contreras, Lellys M. Alshamaa, Hassan Mohamad Clemente Jiménez, Josefa María Rodríguez Vico, Felipe Las Heras Vázquez, Francisco Javier Martínez Rodríguez, Sergio Crystallization of β-xylosidase XynB2 Glycoside Hydrolase Family 52 β-xylosidases (4-β-D-xylan xylohydrolase, E.C. 3.2.1.37) are glycoside hydrolases (GH) catalyzing the hydrolysis of (1→4)-β-D-xylans, allowing for the removal of β-D-xylose residues from its non-reducing termini. Together with other xylan-degrading enzymes, β-xylosidases are involved in the enzymatic hydrolysis of lignocellulosic biomass, making them highly valuable in the biotechnological field. Whereas different GH families are deeply characterized from a structural point of view, the GH52 family has been barely described. In this work, we report the 2.25 Å resolution structure of Geobacillus stearothermophilus CECT43 XynB2, providing the second structural characterization for this GH family. A plausible dynamic loop closing the entrance of the catalytic cleft is proposed based on the comparison of the available GH52 structures, suggesting the relevance of a dimeric structure for members of this family. The glycone specificity at the −1 site for GH52 and GH116 members is also explained by our structural studies. 2024-04-19T09:25:15Z 2024-04-19T09:25:15Z 2023-12-24 journal article Gavira, J.A.; Contreras, L.M.; Alshamaa, H.M.; Clemente-Jiménez, J.M.; Rodríguez-Vico, F.; Las Heras- Vázquez, F.J.; Martínez-Rodríguez, S. Structural Characterization of β-Xylosidase XynB2 from Geobacillus stearothermophilus CECT43: A Member of the Glycoside Hydrolase Family GH52. Crystals 2024, 14, 18. https://doi.org/10.3390/cryst14010018 https://hdl.handle.net/10481/90920 10.3390/cryst14010018 eng http://creativecommons.org/licenses/by/4.0/ open access Atribución 4.0 Internacional MDPI