8Z43

Beta-galactosidase from Bacteroides xylanisolvens (E350G, ligand-free)

8Z43 の概要

• エントリーDOI: 10.2210/pdb8z43/pdb
• 分子名称: Beta-galactosidase, GLYCEROL (3 entities in total)
• 機能のキーワード: glycoside hydrolase, hydrolase
• 由来する生物種: Bacteroides xylanisolvens XB1A
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 125233.03

構造登録者

Nakajima, M.,Motouchi, S.,Kobayashi, K. (登録日: 2024-04-16, 公開日: 2025-01-01, 最終更新日: 2025-03-19)

主引用文献

Nakazawa, Y.,Kageyama, M.,Matsuzawa, T.,Liang, Z.,Kobayashi, K.,Shimizu, H.,Maeda, K.,Masuhiro, M.,Motouchi, S.,Kumano, S.,Tanaka, N.,Kuramochi, K.,Nakai, H.,Taguchi, H.,Nakajima, M.
Structure and function of a beta-1,2-galactosidase from Bacteroides xylanisolvens, an intestinal bacterium.
Commun Biol, 8:66-66, 2025

PubMed Abstract: Galactosides are major carbohydrates that are found in plant cell walls and various prebiotic oligosaccharides. Studying the detailed biochemical functions of β-galactosidases in degrading these carbohydrates is important. In particular, identifying β-galactosidases with new substrate specificities could help in the production of potentially beneficial oligosaccharides. In this study, we identify a β-galactosidase with novel substrate specificity from Bacteroides xylanisolvens, an intestinal bacterium. The enzyme do not show hydrolytic activity toward natural β-galactosides during the first screening. However, when α-D-galactosyl fluoride (α-GalF) as a donor substrate and galactose or D-fucose as an acceptor substrate are incubated with a nucleophile mutant, reaction products are detected. The galactobiose produced from the α-GalF and galactose is identified as β-1,2-galactobiose using NMR. Kinetic analysis reveals that this enzyme effectively hydrolyzes β-1,2-galactobiose and β-1,2-galactotriose. In the complex structure with methyl β-galactopyranose as a ligand, the ligand is only located at subsite +1. The 2-hydroxy group and the anomeric methyl group of methyl β-galactopyranose faces in the direction of subsite -1 and the solvent, respectively. This observation is consistent with the substrate specificity of the enzyme regarding linkage position and chain length. Overall, we conclude that the enzyme is a β-galactosidase acting on β-1,2-galactooligosaccharides.

PubMed: 39820076
DOI: 10.1038/s42003-025-07494-1

実験手法

X-RAY DIFFRACTION (1.91 Å)