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

• Saburi, Wataru

• Okuyama, Masayuki

• Kumagai, Yuya

• Kimura, Atsuo

• Mori, Haruhide

抄録

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.

収録刊行物

• Biochimie

  Biochimie 108 140-148, 2015-01

  Elsevier

キーワード

• alpha-Glucosidase
• Glycoside hydrolase family 31
• Substrate specificity
• Neotrehalose
• Transglucosylation

詳細情報

• CRID: 1050001202677782400
• NII論文ID: 120005595703
• NII書誌ID: AA00564792
• HANDLE: 2115/58508
• ISSN: 03009084
• 本文言語コード: en
• 資料種別: journal article
• データソース種別:
  • IRDB
  • CiNii Articles