7EEE

Complex structure of glycoside hydrolase family 12 beta-1,3-1,4-glucanase with gentiobiose

Summary for 7EEE

• Entry DOI: 10.2210/pdb7eee/pdb
• Descriptor: glycoside hydrolase family 12 beta-1,3-1,4-glucanase, beta-D-mannopyranose-(1-6)-beta-D-mannopyranose, GLYCEROL, ... (4 entities in total)
• Functional Keywords: glucanase, hydrolase, catalytic mechanism, substrate binding, structural protein
• Biological source: Chaetomium sp.
• Total number of polymer chains: 1
• Total formula weight: 26096.51

Authors

Jiang, Z.Q.,Ma, J.W. (deposition date: 2021-03-18, release date: 2022-03-23, Last modification date: 2024-11-06)

Primary citation

Ma, J.,Li, Y.,Han, S.,Jiang, Z.,Yan, Q.,Yang, S.
Structural and biochemical insights into the substrate-binding mechanism of a glycoside hydrolase family 12 beta-1,3-1,4-glucanase from Chaetomium sp.
J.Struct.Biol., 213:107774-107774, 2021

PubMed 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 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.

PubMed: 34329700
DOI: 10.1016/j.jsb.2021.107774

Experimental method

X-RAY DIFFRACTION (1.66079204131 Å)