Junjarus SermsathanaswadiSirilak BarameeChakrit TachaapaikoonPatthra PasonKhanok RatanakhanokchaiAkihiko Kosugi2025-03-102025-03-102017Enzyme and Microbial Technology141022910.1016/j.enzmictec.2016.09.0152-s2.0-84990866300https://repository.dusit.ac.th//handle/123456789/4810A newly isolated endo-_-1,4-xylanase (Xyn10E) from Paenibacillus curdlanolyticus B-6 has a modular structure consisting of a family 22 carbohydrate-binding module (CBM), a glycoside hydrolase (GH) family 10 catalytic domain, two fibronectin type III (Fn3) domains, and a family 3 CBM at the C-terminus. Intact Xyn10E (rXyn10E), CBM22-deleted Xyn10E (X-CBM3), CBM3-deleted Xyn10E (X-CBM22), and GH10 catalytic domain only (X-GH10) were expressed in Escherichia coli. rXyn10E showed bifunctional degradation activity toward xylan and _-glucan and also degraded microcrystalline cellulose. Although X-CBM3 and X-GH10 had drastically reduced xylanase and _-glucanase activities, X-CBM22 mostly retained these activities. Similar Km values were obtained for rXyn10E and X-CBM3, but kcat and kcat/Km values for X-CBM3 and X-GH10 were lower than those for rXyn10E, suggesting that CBM22 of Xyn10E may contribute to catalytic efficiency. In binding assays, X-CBM3 was still able to bind to _-glucan, soluble xylan, insoluble xylan, and cellulose through GH10 and CBM3. These results indicate that CBM22 has an important role not only in binding to xylan and _-glucan but also in feeding both polysaccharides into the neighboring GH10 catalytic domain. rXyn10E showed remarkable synergism with rXyn11A, a major xylanase subunit of P. curdlanolyticus B-6, in the degradation of untreated corn stover and sugarcane bagasse; however, the combination of X-CBM3 and rXyn11A was not synergistic. These results indicate that Xyn10E and Xyn11A act synergistically on lignocellulosic biomass, and CBM22 is essential for efficient degradation of lignocellulosic materials. � 2016 Elsevier Inc.BifunctionalCBM22GH10Paenibacillus curdlanolyticusXylanase_-GlucanaseArticleScopus