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Biochemical properties and substrate recognition mechanism of GH31 alpha-glucosidase from Bacillus sp AHU 2001 with broad substrate specificity

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Title: Biochemical properties and substrate recognition mechanism of GH31 alpha-glucosidase from Bacillus sp AHU 2001 with broad substrate specificity
Authors: Saburi, Wataru Browse this author →KAKEN DB
Okuyama, Masayuki Browse this author →KAKEN DB
Kumagai, Yuya Browse this author →KAKEN DB
Kimura, Atsuo Browse this author →KAKEN DB
Mori, Haruhide Browse this author →KAKEN DB
Keywords: alpha-Glucosidase
Glycoside hydrolase family 31
Substrate specificity
Neotrehalose
Transglucosylation
Issue Date: Jan-2015
Publisher: Elsevier
Journal Title: Biochimie
Volume: 108
Start Page: 140
End Page: 148
Publisher DOI: 10.1016/j.biochi.2014.11.010
PMID: 25450253
Abstract: alpha-Glucosidases are ubiquitous enzymes that hydrolyze the alpha-glucosidic linkage at the non-reducing end of substrates. In this study, we characterized an alpha-glucosidase (BspAG31A) belonging to glycoside hydrolase family 31 from Bacillus sp. AHU 2001. Recombinant B5pAG31A, produced in Escherichia colt, had high hydrolytic activity toward maltooligosaccharides, kojibiose, nigerose, and neotrehalose. This is the first report of an alpha-glucosidase with high activity toward neotrehalose. The transglucosylation products, nigerose, kojibiose, isomaltose, and neotrehalose, were generated from 440 mm maltose. Substitution of Tyr268, situated on the beta -> alpha loop 1 of B5pAG31A, with Trp increased hydrolytic activity toward isomaltose. This mutation reduced the hydrolytic activity toward maltooligosaccharides more than toward kojibiose, nigerose, and neotrehalose. Analysis of the Y173A mutant of B5pAG31A showed that Tyr173, situated on the N-terminal domain loop, is associated with the formation of subsite +2. In Y173A, the k(cad)/K-m for maltooligosaccharides slightly decreased with an increasing degree of polymerization compared with wild type. Among the amino acid residues surrounding the substrate binding site, Va1543 and Glu545 of B5pAG31A were different from the corresponding residues of Bacillus thermoamyloliquefaciens alpha-glucosidase II, which has higher activity toward isomaltose than B5pAG31A. The E545G mutation slightly enhanced isomaltase activity without a large reduction of hydrolytic activities toward other substrates. V543A showed 1.8-3.5-fold higher hydrolytic activities toward all substrates other than neotrehalose compared with wild type, although its preference for isomaltose was unchanged. (C) 2014 Elsevier B.V. and Societe francaise de biochimie et biologie Moleculaire (SFBBM). All rights reserved.
Type: article (author version)
URI: http://hdl.handle.net/2115/58508
Appears in Collections:農学院・農学研究院 (Graduate School of Agriculture / Faculty of Agriculture) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)

Submitter: 森春英

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