Glycosyl hydrolase family 20 (GH20) catalytic domain of dispersin B (DspB), lacto-N-biosidase (LnbB) and related proteins. Dispersin B is a soluble beta-N-acetylglucosamidase found in bacteria that hydrolyzes the beta-1,6-linkages of PGA (poly-beta-(1,6)-N-acetylglucosamine), a major component of the extracellular polysaccharide matrix. Lacto-N-biosidase hydrolyzes lacto-N-biose (LNB) type I oligosaccharides at the nonreducing terminus to produce lacto-N-biose as part of the GNB/LNB (galacto-N-biose/lacto-N-biose I) degradation pathway. The lacto-N-biosidase from Bifidobacterium bifidum has this GH20 domain, a carbohydrate binding module 32, and a bacterial immunoglobulin-like domain 2, as well as a YSIRK signal peptide and a G5 membrane anchor at the N and C termini, respectively. The GH20 hexosaminidases are thought to act via a catalytic mechanism in which the catalytic nucleophile is not provided by solvent or the enzyme, but by the substrate itself.

Glycosyl hydrolase family 20, catalytic domain. This domain has a TIM barrel fold.

Beta-N-acetylhexosaminidases of glycosyl hydrolase family 20 (GH20) catalyze the removal of beta-1,4-linked N-acetyl-D-hexosamine residues from the non-reducing ends of N-acetyl-beta-D-hexosaminides including N-acetylglucosides and N-acetylgalactosides. These enzymes are broadly distributed in microorganisms, plants and animals, and play roles in various key physiological and pathological processes. These processes include cell structural integrity, energy storage, cellular signaling, fertilization, pathogen defense, viral penetration, the development of carcinomas, inflammatory events and lysosomal storage disorders. The GH20 enzymes include the eukaryotic beta-N-acetylhexosaminidases A and B, the bacterial chitobiases, dispersin B, and lacto-N-biosidase. The GH20 hexosaminidases are thought to act via a catalytic mechanism in which the catalytic nucleophile is not provided by the solvent or the enzyme, but by the substrate itself.

The chitobiase of Serratia marcescens is a beta-N-1,4-acetylhexosaminidase with a glycosyl hydrolase family 20 (GH20) domain that hydrolyzes the beta-1,4-glycosidic linkages in oligomers derived from chitin. Chitin is degraded by a two step process: i) a chitinase hydrolyzes the chitin to oligosaccharides and disaccharides such as di-N-acetyl-D-glucosamine and chitobiose, ii) chitobiase then further degrades these oligomers into monomers. This GH20 domain family includes an N-acetylglucosamidase (GlcNAcase A) from Pseudoalteromonas piscicida and an N-acetylhexosaminidase (SpHex) from Streptomyces plicatus. SpHex lacks the C-terminal PKD (polycystic kidney disease I)-like domain found in the chitobiases. The GH20 hexosaminidases are thought to act via a catalytic mechanism in which the catalytic nucleophile is not provided by solvent or the enzyme, but by the substrate itself.

N-acetyl-beta-hexosaminidase [Carbohydrate transport and metabolism].

Crystallizationanalysis of a beta-N-acetylhexosaminidase (Am2136) from Akkermansia muciniphila [Akkermansia muciniphila ATCC BAA-835]

ChainA, Fibronectin type III domain-containing protein [Tyzzerella nexilis]

ChainA, Lacto-N-biosidase [Bifidobacterium saguini DSM 23967]

Crystalstructure of lacto-N-biosidase LnbX from Bifidobacterium longum subsp. longum, ligand-free form [Bifidobacterium longum subsp. longum],5GQC_B Crystal structure of lacto-N-biosidase LnbX from Bifidobacterium longum subsp. longum, ligand-free form [Bifidobacterium longum subsp. longum],5GQC_C Crystal structure of lacto-N-biosidase LnbX from Bifidobacterium longum subsp. longum, ligand-free form [Bifidobacterium longum subsp. longum],5GQC_D Crystal structure of lacto-N-biosidase LnbX from Bifidobacterium longum subsp. longum, ligand-free form [Bifidobacterium longum subsp. longum],5GQC_E Crystal structure of lacto-N-biosidase LnbX from Bifidobacterium longum subsp. longum, ligand-free form [Bifidobacterium longum subsp. longum],5GQC_F Crystal structure of lacto-N-biosidase LnbX from Bifidobacterium longum subsp. longum, ligand-free form [Bifidobacterium longum subsp. longum],5GQC_G Crystal structure of lacto-N-biosidase LnbX from Bifidobacterium longum subsp. longum, ligand-free form [Bifidobacterium longum subsp. longum],5GQC_H Crystal structure of lacto-N-biosidase LnbX from Bifidobacterium longum subsp. longum, ligand-free form [Bifidobacterium longum subsp. longum],5GQF_A Crystal structure of lacto-N-biosidase LnbX from Bifidobacterium longum subsp. longum, lacto-N-biose complex [Bifidobacterium longum subsp. longum],5GQF_B Crystal structure of lacto-N-biosidase LnbX from Bifidobacterium longum subsp. longum, lacto-N-biose complex [Bifidobacterium longum subsp. longum],5GQG_A Crystal structure of lacto-N-biosidase LnbX from Bifidobacterium longum subsp. longum, galacto-N-biose complex [Bifidobacterium longum subsp. longum],5GQG_B Crystal structure of lacto-N-biosidase LnbX from Bifidobacterium longum subsp. longum, galacto-N-biose complex [Bifidobacterium longum subsp. longum]

CrystalStructure of GH136 lacto-N-biosidase from Eubacterium ramulus - native protein [Eubacterium ramulus ATCC 29099]

Beta-hexosaminidase Amuc_2136 OS=Akkermansia muciniphila (strain ATCC BAA-835 / DSM 22959 / JCM 33894 / BCRC 81048 / CCUG 64013 / CIP 107961 / Muc) OX=349741 GN=Amuc_2136 PE=1 SV=1

Beta-hexosaminidase OS=Vibrio furnissii OX=29494 GN=exoI PE=1 SV=1

Beta-hexosaminidase Amuc_2018 OS=Akkermansia muciniphila (strain ATCC BAA-835 / DSM 22959 / JCM 33894 / BCRC 81048 / CCUG 64013 / CIP 107961 / Muc) OX=349741 GN=Amuc_2018 PE=1 SV=1

Beta-hexosaminidase OS=Porphyromonas gingivalis (strain ATCC BAA-308 / W83) OX=242619 GN=nahA PE=3 SV=2

Beta-hexosaminidase subunit alpha OS=Homo sapiens OX=9606 GN=HEXA PE=1 SV=2