8OI4
Metagenomic Beta-galactosidase from Glycoside Hydrolase family GH154
Summary for 8OI4
| Entry DOI | 10.2210/pdb8oi4/pdb |
| Descriptor | Beta-galactosidase, GLYCEROL, CHLORIDE ION, ... (4 entities in total) |
| Functional Keywords | beta-galactosidase, glycoside hydrolase family 154, carbohydrate degradation, hydrolase |
| Biological source | organismal metagenomes |
| Total number of polymer chains | 4 |
| Total formula weight | 185798.00 |
| Authors | Pijning, T.,Hameleers, L.,Jurak, E.,Guskov, A. (deposition date: 2023-03-22, release date: 2024-01-31) |
| Primary citation | 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 Cited by 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: 38163476DOI: 10.1016/j.nbt.2023.12.011 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (1.76 Å) |
Structure validation
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