title: Identification of the Gene Encoding Isoprimeverose-producing Oligoxyloglucan Hydrolase in Aspergillus oryzae.
abstract: Aspergillus oryzae produces a unique β-glucosidase, isoprimeverose-producing oligoxyloglucan hydrolase (IPase), that recognizes and releases isoprimeverose (α-D-xylopyranose-(1 → 6)-D-glucopyranose) units from the non-reducing ends of oligoxyloglucans. A gene encoding A. oryzae IPase, termed ipeA, was identified and expressed in Pichia pastoris. With the exception of cellobiose, IpeA hydrolyzes a variety of oligoxyloglucans and is a member of the glycoside hydrolase family 3. Xylopyranosyl branching at the non-reducing ends was vital for IPase activity, and galactosylation at a α-1,6-linked xylopyranosyl side chain completely abolished IpeA activity. Hepta-oligoxyloglucan saccharide (Xyl3Glc4) substrate was preferred over tri- (Xyl1Glc2) and tetra- (Xyl2Glc2) oligoxyloglucan saccharides substrates. IpeA transferred isoprimeverose units to other saccharides, indicating transglycosylation activity. The ipeA gene was expressed in xylose and xyloglucan media and was strongly induced in the presence of xyloglucan endo-xyloglucanase-hydrolyzed products. This is the first study to report the identification of a gene encoding IPase in eukaryotes.
authors.affiliation: From the Bioproduction Research Institute and.
authors.forename: Tomohiko
authors.initials: T
authors.lastname: Matsuzawa
authors.affiliation: From the Bioproduction Research Institute and.
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Mitsuishi
authors.affiliation: Department of Life Science and Biotechnology, National Institute of Advanced Industrial Science and Technology, Tsukuba Central 6, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8566, Japan.
authors.forename: Akihiko
authors.initials: A
authors.lastname: Kameyama
authors.affiliation: From the Bioproduction Research Institute and k-yaoi@aist.go.jp.
authors.forename: Katsuro
authors.identifier: http://orcid.org/0000-0002-4037-0087
authors.initials: K
authors.lastname: Yaoi
mesh_terms: D000595:Amino Acid Sequence; D001236:Aspergillus oryzae / Q000201:enzymology* / Q000235:genetics; D001483:Base Sequence; D004187:Disaccharides / Q000378:metabolism*; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D006026:Glycoside Hydrolases / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D010802:Phylogeny; D013379:Substrate Specificity
chemical_list: D004187:Disaccharides; D005656:Fungal Proteins; C046205:isoprimeverose; D006026:Glycoside Hydrolases; C046206:oligoxyloglucan hydrolase
keywords: Aspergillus; carbohydrate; cloning; glycoside hydrolase; isoprimeverose; recombinant protein expression; substrate specificity; xyloglucan