Mannosyl-glycoprotein endo-beta-N-acetylglucosaminidase
Endo-beta-N-acetylglucosaminidases cleave asparagine-linked oligomannose and hybrid, but not complex, oligosaccharides from glycoproteins [PMID:11515537]. They belong to glycosyl hydrolase family 18.
Reference Protein and Structure
- Sequence
-
P36911
(3.2.1.96)
(Sequence Homologues)
(PDB Homologues)
- Biological species
-
Elizabethkingia meningoseptica (Bacteria)
- PDB
-
2ebn
- CRYSTAL STRUCTURE OF ENDO-BETA-N-ACETYLGLUCOSAMINIDASE F1, AN ALPHA(SLASH)BETA-BARREL ENZYME ADAPTED FOR A COMPLEX SUBSTRATE
(2.0 Å)
- Catalytic CATH Domains
-
3.20.20.80
(see all for 2ebn)
Enzyme Reaction (EC:3.2.1.96)
+
→
+
Alternative enzyme names: N,N'-diacetylchitobiosyl beta-N-acetylglucosaminidase, Di-N-acetylchitobiosyl beta-N-acetylglucosaminidase, Endo-N-acetyl-beta-D-glucosaminidase, Endo-N-acetyl-beta-glucosaminidase, Endo-beta-(1->4)-N-acetylglucosaminidase, Endo-beta-N-acetylglucosaminidase, Endo-beta-N-acetylglucosaminidase D, Endo-beta-N-acetylglucosaminidase F, Endo-beta-N-acetylglucosaminidase H, Endo-beta-N-acetylglucosaminidase L, Endo-beta-acetylglucosaminidase, Endoglycosidase S, Mannosyl-glycoprotein 1,4-N-acetamidodeoxy-beta-D-glycohydrolase, Mannosyl-glycoprotein endo-beta-N-acetylglucosamidase, Glycopeptide-D-mannosyl-4-N-(N-acetyl-D-glucosaminyl)(2)-asparagine 1,4-N-acetyl-beta-glucosaminohydrolase, Endoglycosidase H,
Enzyme Mechanism
Introduction
It has been proposed that the family 18 glycohydrolases function via a substrate-assisted mechanism, involving only one acid residue. In this mechanism, Glu132 acts as the proton donor, and the N-acetyl group of the leaving GlcNAc acts as the nucleophile. Asp130 would stabilise the positive charge on the nitrogen of the N-acetyl group in the transition state intermediate.
Catalytic Residues Roles
| UniProt | PDB* (2ebn) | ||
| Asp180 | Asp130A | Acts to stabilise the transition states formed during the course of the reaction. | electrostatic stabiliser |
| Glu182 | Glu132A | Acts as a general acid/base. | proton shuttle (general acid/base) |
*PDB label guide - RESx(y)B(C) - RES: Residue Name; x: Residue ID in PDB file;
y: Residue ID in PDB sequence if different from PDB file; B: PDB Chain;
C: Biological Assembly Chain if different from PDB. If label is "Not Found" it means this residue is not found in the reference PDB.
Chemical Components
References
- Rao V et al. (1999), Protein Sci, 8, 2338-2346. Mutations of endo-beta-N-acetylglucosaminidase H active site residueAs sp130 anG glu132: activities and conformations. DOI:10.1110/ps.8.11.2338. PMID:10595536.
- Fujita K et al. (2001), Biosci Biotechnol Biochem, 65, 1542-1548. Identification of amino acid residues essential for the substrate specificity of Flavobacterium sp. endo-beta-N-acetylglucosaminidase. DOI:10.1271/bbb.65.1542. PMID:11515537.
- Davies G et al. (1995), Structure, 3, 853-859. Structures and mechanisms of glycosyl hydrolases. DOI:10.1016/s0969-2126(01)00220-9. PMID:8535779.
- Van Roey P et al. (1994), Biochemistry, 33, 13989-13996. Crystal structure of endo-beta-N-acetylglucosaminidase F1, an alpha/beta-barrel enzyme adapted for a complex substrate. PMID:7947807.
Catalytic Residues Roles
| Residue | Roles |
|---|---|
| Asp130A | electrostatic stabiliser |
| Glu132A | proton shuttle (general acid/base) |