8OUG

Exo-beta-d-glucosaminidase from Pyrococcus chitonophagus

Summary for 8OUG

• Entry DOI: 10.2210/pdb8oug/pdb
• Descriptor: Beta-galactosidase, 1,2-ETHANEDIOL, CHLORIDE ION, ... (4 entities in total)
• Functional Keywords: hyperthermophile, hydrolase
• Biological source: Thermococcus chitonophagus
• Total number of polymer chains: 1
• Total formula weight: 92917.30

Authors

Rypniewski, W.,Biniek-Antosiak, K.,Bejger, M. (deposition date: 2023-04-22, release date: 2024-05-01, Last modification date: 2026-06-03)

Primary citation

Biniek-Antosiak, K.,Baranowski, D.,Sliwiak, J.,Milik, M.,Bejger, M.,Rypniewski, W.
Crystal structure, thermostability and temperature-dependent enzymatic activity of an exo-beta-d-glucosaminidase from Pyrococcus chitonophagus.
J.Struct.Biol., :108327-108327, 2026

PubMed Abstract: Pch-GlmA is a hyperthermophilic GH35 exo-β-d-glucosaminidase whose structure closely resembles its archaeal homologs, yet its functional behavior differs markedly. Calorimetric and fluorimetric temperature scans consistently reveal a complex thermodynamic profile of the enzyme, characterized by distinct thermal transitions. The freshly purified protein appears to be monomeric and required thermal annealing to attain its biologically relevant dimeric state. Catalytic activity is observed only above 75 °C, where the enzyme specifically hydrolyses the glycosidic bond of GlcN-GlcNAc. These findings support a sequential role for Pch-GlmA alongside Pch-Dac in the processing of chitin-derived carbohydrates. Comparison with related GlmA proteins demonstrates that substantial structural similarity does not necessarily translate into equivalent enzymatic properties and that hyperthermophilic enzymes may operate within narrow temperature ranges. Overall, this work underscores the importance of experimental validation when interpreting or predicting the activity of enzymes derived from extremophiles.

PubMed: 42177926
DOI: 10.1016/j.jsb.2026.108327

Experimental method

X-RAY DIFFRACTION (2.1 Å)