7F7Q

Enterococcus faecalis GH31 alpha-N-acetylgalactosaminidase D455A in complex with p-nitrophenyl alpha-N-acetylgalactosaminide

7F7Q の概要

• エントリーDOI: 10.2210/pdb7f7q/pdb
• 分子名称: GH31 alpha-N-acetylgalactosaminidase, 2-acetamido-2-deoxy-alpha-D-galactopyranose, P-NITROPHENOL, ... (6 entities in total)
• 機能のキーワード: glycoside hydrolase, gh31, mucin, (beta/alpha)8-barrel, fibronectin-like, substrate, complex, hydrolase
• 由来する生物種: Enterococcus faecalis ATCC 10100
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 107679.77

構造登録者

Miyazaki, T. (登録日: 2021-06-30, 公開日: 2021-12-08, 最終更新日: 2023-11-29)

主引用文献

Miyazaki, T.,Ikegaya, M.,Alonso-Gil, S.
Structural and mechanistic insights into the substrate specificity and hydrolysis of GH31 alpha-N-acetylgalactosaminidase.
Biochimie, 195:90-99, 2022

PubMed Abstract: Glycoside hydrolase family 31 (GH31) is a diversified family of anomer-retaining α-glycoside hydrolases, such as α-glucosidase and α-xylosidase, among others. Recently, GH31 α-N-acetylgalactosaminidases (Nag31s) have been identified to hydrolyze the core of mucin-type O-glycans and the crystal structure of a gut bacterium Enterococcus faecalis Nag31 has been reported. However, the mechanisms of substrate specificity and hydrolysis of Nag31s are not well investigated. Herein, we show that E. faecalis Nag31 has the ability to release N-acetylgalactosamine (GalNAc) from O-glycoproteins, such as fetuin and mucin, but has low activity against Tn antigen. Mutational analysis and crystal structures of the Michaelis complexes reveal that residues of the active site work in concert with their conformational changes to act on only α-N-acetylgalactosaminides. Docking simulations using GalNAc-attached peptides suggest that the enzyme mainly recognizes GalNAc and side chains of Ser/Thr, but not strictly other peptide residues. Moreover, quantum mechanics calculations indicate that the enzyme preferred p-nitrophenyl α-N-acetylgalactosaminide to Tn antigen and that the hydrolysis progresses through a conformational itinerary, C → S → C, in GalNAc of substrates. Our results provide novel insights into the diversification of the sugar recognition and hydrolytic mechanisms of GH31 enzymes.

PubMed: 34826537
DOI: 10.1016/j.biochi.2021.11.007

実験手法

X-RAY DIFFRACTION (1.42 Å)