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The basidiomycetePhanerochaete chrysosporiumproduces xyloglucanase Xgh74B, which has the glycoside hydrolase (GH) family 74 catalytic domain and family 1 carbohydrate-binding module, in cellulose-grown cul-ture. | ỊFEBS Journal Substrate recognition by glycoside hydrolase family 74 xyloglucanase from the basidiomycete Phanerochaete chrysosporium Takuya Ishida1 Katsuro Yaoi2 Ayako Hiyoshi2 Kiyohiko Igarashi1 and Masahiro Samejima1 1 Department of Biomaterials Sciences Graduate Schoolof Agriculturaland Life Sciences University of Tokyo Japan 2 Institute for BiologicalResources and Functions NationalInstitute of Advanced IndustrialScience and Technology AIST Tsukuba Japan Keywords glycoside hydrolase Phanerochaete chrysosporium Xgh74B xyloglucan xyloglucanase Correspondence M. Samejima Department of Biomaterials Sciences Graduate School of Agricultural and Life Sciences The University of Tokyo 1-1-1 Yayoi Bunkyo-ku Tokyo 113-8657 Japan Fax 81 3 5841 5273 Tel 81 3 5841 5255 E-mail amsam@mail.ecc.u-tokyo.ac.jp Database The sequences of the cDNAs encoding Phanerochaete chrysosporium Xgh74B have been submitted to the DNA Data Bank of the Japan European Molecular Biology Lab-oratory GenBank databases under accession number AB308054 Received 18 June 2007 revised 19 July 2007 accepted 5 September 2007 The basidiomycete Phanerochaete chrysosporium produces xyloglucanase Xgh74B which has the glycoside hydrolase GH family 74 catalytic domain and family 1 carbohydrate-binding module in cellulose-grown culture. The recombinant enzyme which was heterologously expressed in the yeast Pichia pastoris had high hydrolytic activity toward xyloglucan from tamarind seed TXG whereas other b-1 4-glucans examined were poor substrates for the enzyme. The existence of the carbohydrate-binding module significantly affects adsorption of the enzyme on crystalline cellulose but has no effect on the hydrolysis of xyloglucan indicating that the domain may contribute to the localization of the enzyme. HPLC and MALDI-TOF MS analyses of the hydrolytic products of TXG clearly indicated that Xgh74B hydrolyzes the glycosidic bonds of unbranched glucose residues like other GH family 74 xyloglucanases. However .
