tailieunhanh - Báo cáo khoa học: The crystal structure of a xyloglucan-specific endo-b-1,4glucanase from Geotrichum sp. M128 xyloglucanase reveals a key amino acid residue for substrate specificity

Geotrichumsp. M128 possesses two xyloglucan-specific glycoside hydrolases belonging to family 74, xyloglucan-specific endo-b-1,4-glucanase (XEG) and oligoxyloglucan reducing-end-specific cellobiohydrolase (OXG-RCBH). Despite their similar amino acid sequences (48% identity), their modes of action and substrate specificities are distinct. | The crystal structure of a xyloglucan-specific endo-p-1 4-glucanase from Geotrichum sp. M128 xyloglucanase reveals a key amino acid residue for substrate specificity Katsuro Yaoi1 Hidemasa Kondo2 Ayako Hiyoshi1 Natsuko Noro2 Hiroshi Sugimoto3 Sakae Tsuda2 4 and Kentaro Miyazaki1 5 1 Institute for BiologicalResources and Functions National institute of Advanced Industrial science and Technology AIST Tsukuba Ibaraki Japan 2 Research Institute of Genome-based Biofactory NationalInstitute of Advanced Industrial science and Technology AIST Toyohira Sapporo Hokkaido Japan 3 Riken SPring-8 Center Harima Institute Hyogo Japan 4 Division of BiologicalScience Graduate Schoolof Science Hokkaido University Sapporo Japan 5 Department of MedicalGenome Sciences Graduate Schoolof Frontier Sciences The University of Tokyo Tsukuba Ibaraki Japan Keywords endo-b-1 4-glucanase glycoside hydrolase family 74 xyloglucan xyloglucanase b-1 4-glucan Correspondence K. Yaoi Institute for BiologicalResources and Functions National Institute of Advanced IndustrialScience and Technology AIST Tsukuba Central6 1-1-1 Higashi Tsukuba Ibaraki 305-8566 Japan Fax 81 29 861 6733 Tel 81 29 861 6065 E-mail k-yaoi@ These authors contributed equally to this study Database The coordinates of the structure for XEG have been deposited in the Protein Data Bank under the accession number 3A0F Received 14 May 2009 revised 3 July 2009 accepted 8 July 2009 Geotrichum sp. M128 possesses two xyloglucan-specific glycoside hydrolases belonging to family 74 xyloglucan-specific endo-b-1 4-glucanase XEG and oligoxyloglucan reducing-end-specific cellobiohydrolase OXG-RCBH . Despite their similar amino acid sequences 48 identity their modes of action and substrate specificities are distinct. XEG catalyzes the hydrolysis of xyloglucan polysaccharides in endo mode while OXG-RCBH acts on xyloglucan oligosaccharides at the reducing end in exo mode. Here we determined the crystal structure of XEG at A resolution and