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Structural and biochemical insights into the substrate-binding mechanism of a glycoside hydrolase family 12 β-1,3-1,4-glucanase from Chaetomium sp
- Source :
- Journal of structural biology. 213(3)
- Publication Year :
- 2021
-
Abstract
- β-1,3-1,4-Glucanases are a type of hydrolytic enzymes capable of catalyzing the strict cleavage of β-1,4 glycosidic bonds adjacent to β-1,3 linkages in β-D-glucans and have exhibited great potential in food and feed industrials. In this study, a novel glycoside hydrolase (GH) family 12 β-1,3-1,4-glucanase (CtGlu12A) from the thermophilic fungus Chaetomium sp. CQ31 was identified and biochemically characterized. CtGlu12A was most active at pH 7.5 and 65 °C, respectively, and exhibited a high specific activity of 999.9 U mg−1 towards lichenin. It maintained more than 80% of its initial activity in a wide pH range of 5.0–11.0, and up to 60 °C after incubation at 55 °C for 60 min. Moreover, the crystal structures of CtGlu12A with gentiobiose and tetrasccharide were resolved. CtGlu12A had a β-jellyroll fold, and performed retaining mechanism with two glutamic acids severing as the catalytic residues. In the complex structure, cellobiose molecule showed two binding modes, occupying subsites −2 to −1 and subsites + 1 to + 2, respectively. The concave cleft made mixed β-1,3-1,4-glucan substrates maintain a bent conformation to fit into the active site. Overall, this study is not only helpful for the understanding of the substrate-binding model and catalytic mechanism of GH 12 β-1,3-1,4-glucanases, but also provides a basis for further enzymatic engineering of β-1,3-1,4-glucanases.
- Subjects :
- chemistry.chemical_classification
biology
Glycoside Hydrolases
Chemistry
Stereochemistry
Hydrolysis
Active site
Glycosidic bond
Lichenin
Cellobiose
Glucanase
Chaetomium
Substrate Specificity
chemistry.chemical_compound
Enzyme
Structural Biology
Catalytic Domain
biology.protein
Gentiobiose
Glycoside hydrolase
Subjects
Details
- ISSN :
- 10958657
- Volume :
- 213
- Issue :
- 3
- Database :
- OpenAIRE
- Journal :
- Journal of structural biology
- Accession number :
- edsair.doi.dedup.....f3b73c9bda9fb4089bd40e3abff4a802