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Function and structure of GH 13_31 α‐glucosidase with high α‐(1→4)‐glucosidic linkage specificity and transglucosylation activity
Author(s) -
Auiewiriyanukul Waraporn,
Saburi Wataru,
Kato Koji,
Yao Min,
Mori Haruhide
Publication year - 2018
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1002/1873-3468.13126
Subject(s) - hydrolase , glycoside hydrolase , chemistry , stereochemistry , maltose , enzyme , mutant , substrate (aquarium) , biochemistry , biology , gene , ecology
α‐Glucosidase hydrolyzes α‐glucosides and transfers α‐glucosyl residues to an acceptor through transglucosylation. In this study, GH 13_31 α‐glucosidase Bsp AG 13_31A with high transglucosylation activity is reported in Bacillus sp. AHU 2216 and biochemically and structurally characterized. This enzyme is specific to α‐(1→4)‐glucosidic linkage as substrates and transglucosylation products. Maltose is the most preferred substrate. Crystal structures of Bsp AG 13_31A wild‐type for the substrate‐free form and inactive acid/base mutant E256Q in complexes with maltooligosaccharides were solved at 1.6–2.5 Å resolution. Bsp AG 13_31A has a catalytic domain folded by an (β/α) 8 ‐barrel. In subsite +1, Ala200 and His203 on β→α loop 4 and Asn258 on β→α loop 5 are involved in the recognition of maltooligosaccharides. Structural basis for specificity of GH 13_31 enzymes to α‐(1→4)‐glucosidic linkage is first described.