title: The family 22 carbohydrate-binding module of bifunctional xylanase/β-glucanase Xyn10E from Paenibacillus curdlanolyticus B-6 has an important role in lignocellulose degradation.
abstract: A newly isolated endo-β-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 β-glucan and also degraded microcrystalline cellulose. Although X-CBM3 and X-GH10 had drastically reduced xylanase and β-glucanase activities, X-CBM22 mostly retained these activities. Similar Kmvalues were obtained for rXyn10E and X-CBM3, but kcatand kcat/Kmvalues 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 β-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 β-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.
authors.affiliation: Department of Chemical Technology, Faculty of Science and Technology, Suan Dusit University, 295 Rajasrima Road, Dusit, Bangkok 10300, Thailand; Biological Resources and Post-harvest Division, Japan International Research Center for Agricultural Sciences (JIRCAS), 1-1 Ohwashi, Tsukuba, Ibaraki 305-8686, Japan.
authors.forename: Junjarus
authors.initials: J
authors.lastname: Sermsathanaswadi
authors.affiliation: School of Bioresources and Technology, King Mongkut's University of Technology Thonburi, Bangkuntien, Bangkok 10150, Thailand.
authors.forename: Sirilak
authors.initials: S
authors.lastname: Baramee
authors.affiliation: Pilot Plant Development and Training Institute, King Mongkut's University of Technology Thonburi, Bangkuntien, Bangkok 10150, Thailand.
authors.forename: Chakrit
authors.initials: C
authors.lastname: Tachaapaikoon
authors.affiliation: Pilot Plant Development and Training Institute, King Mongkut's University of Technology Thonburi, Bangkuntien, Bangkok 10150, Thailand.
authors.forename: Patthra
authors.initials: P
authors.lastname: Pason
authors.affiliation: School of Bioresources and Technology, King Mongkut's University of Technology Thonburi, Bangkuntien, Bangkok 10150, Thailand.
authors.forename: Khanok
authors.initials: K
authors.lastname: Ratanakhanokchai
authors.affiliation: Biological Resources and Post-harvest Division, Japan International Research Center for Agricultural Sciences (JIRCAS), 1-1 Ohwashi, Tsukuba, Ibaraki 305-8686, Japan. Electronic address: akosugi@affrc.go.jp.
authors.forename: Akihiko
authors.initials: A
authors.lastname: Kosugi
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D020134:Catalytic Domain; D043364:Endo-1,4-beta Xylanases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D005798:Genes, Bacterial; D044643:Glucan 1,4-beta-Glucosidase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D007700:Kinetics; D008031:Lignin / Q000378:metabolism*; D056507:Paenibacillus / Q000201:enzymology* / Q000235:genetics; D010802:Phylogeny; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D040681:Structural Homology, Protein; D013379:Substrate Specificity
chemical_list: D001426:Bacterial Proteins; D011994:Recombinant Proteins; C036909:lignocellulose; D008031:Lignin; D044643:Glucan 1,4-beta-Glucosidase; D043364:Endo-1,4-beta Xylanases
keywords: Bifunctional; CBM22; GH10; Paenibacillus curdlanolyticus; Xylanase; β-Glucanase