8OI4

Metagenomic Beta-galactosidase from Glycoside Hydrolase family GH154

8OI4 の概要

• エントリーDOI: 10.2210/pdb8oi4/pdb
• 分子名称: Beta-galactosidase, GLYCEROL, CHLORIDE ION, ... (4 entities in total)
• 機能のキーワード: beta-galactosidase, glycoside hydrolase family 154, carbohydrate degradation, hydrolase
• 由来する生物種: organismal metagenomes
• タンパク質・核酸の鎖数: 4
• 化学式量合計: 185798.00

構造登録者

Pijning, T.,Hameleers, L.,Jurak, E.,Guskov, A. (登録日: 2023-03-22, 公開日: 2024-01-31)

主引用文献

Hameleers, L.,Pijning, T.,Gray, B.B.,Faure, R.,Jurak, E.
Novel beta-galactosidase activity and first crystal structure of Glycoside Hydrolase family 154.
N Biotechnol, 80:1-11, 2023

PubMed Abstract: Polysaccharide Utilization Loci (PULs) are physically linked gene clusters conserved in the Gram-negative phylum of Bacteroidota and are valuable sources for Carbohydrate Active enZyme (CAZyme) discovery. This study focuses on BD-β-Gal, an enzyme encoded in a metagenomic PUL and member of the Glycoside Hydrolase family 154 (GH154). BD-β-Gal showed exo-β-galactosidase activity with regiopreference for hydrolyzing β-d-(1,6) glycosidic linkages. Notably, it exhibited a preference for d-glucopyranosyl (d-Glcp) over d-galactopyranosyl (d-Galp) and d-fructofuranosyl (d-Fruf) at the reducing end of the investigated disaccharides. In addition, we determined the high resolution crystal structure of BD-β-Gal, thus providing the first structural characterization of a GH154 enzyme. Surprisingly, this revealed an (α/α) topology, which has not been observed before for β-galactosidases. BD-β-Gal displayed low structural homology with characterized CAZymes, but conservation analysis suggested that the active site was located in a central cavity, with conserved E73, R252, and D253 as putative catalytic residues. Interestingly, BD-β-Gal has a tetrameric structure and a flexible loop from a neighboring protomer may contribute to its reaction specificity. Finally, we showed that the founding member of GH154, BT3677 from Bacteroides thetaiotaomicron, described as β-glucuronidase, displayed exo-β-galactosidase activity like BD-β-Gal but lacked a tetrameric structure.

PubMed: 38163476
DOI: 10.1016/j.nbt.2023.12.011

実験手法

X-RAY DIFFRACTION (1.76 Å)