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.

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

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

A functionally uncharacterized subgroup of the Glycosyl hydrolase family 20 (GH20) catalytic domain found in proteins similar to the chitobiase of Serratia marcescens, a beta-N-1,4-acetylhexosaminidase 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 subgroup 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.

A subgroup of the Glycosyl hydrolase family 20 (GH20) catalytic domain found in proteins similar to the N-acetylhexosaminidase from Streptomyces plicatus (SpHex). SpHex catalyzes the hydrolysis of N-acetyl-beta-hexosaminides. An Asp residue within the active site plays a critical role in substrate-assisted catalysis by orienting the 2-acetamido group and stabilizing the transition state. 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. Proteins belonging to this subgroup lack the C-terminal PKD (polycystic kidney disease I)-like domain found in the chitobiases.

Crystalstructure of a putative alpha-L-fucosidase (BACOVA_04357) from Bacteroides ovatus ATCC 8483 at 1.59 A resolution [Bacteroides ovatus ATCC 8483]

BT0459[Bacteroides thetaiotaomicron],6Q63_B BT0459 [Bacteroides thetaiotaomicron],6Q63_C BT0459 [Bacteroides thetaiotaomicron]

Crystalstructure of alpha-1,3/4-fucosidase from Bifidobacterium longum subsp. infantis complexed with deoxyfuconojirimycin [Bifidobacterium longum subsp. infantis ATCC 15697 = JCM 1222 = DSM 20088],3UES_B Crystal structure of alpha-1,3/4-fucosidase from Bifidobacterium longum subsp. infantis complexed with deoxyfuconojirimycin [Bifidobacterium longum subsp. infantis ATCC 15697 = JCM 1222 = DSM 20088]

Thecrystal structure of an alpha-(1-3,4)-fucosidase from Bifidobacterium longum subsp. infantis ATCC 15697 [Bifidobacterium longum subsp. infantis ATCC 15697 = JCM 1222 = DSM 20088],3MO4_B The crystal structure of an alpha-(1-3,4)-fucosidase from Bifidobacterium longum subsp. infantis ATCC 15697 [Bifidobacterium longum subsp. infantis ATCC 15697 = JCM 1222 = DSM 20088]

Crystalstructure of alpha-1,3/4-fucosidase from Bifidobacterium longum subsp. infantis D172A/E217A mutant complexed with lacto-N-fucopentaose II [Bifidobacterium longum subsp. infantis ATCC 15697 = JCM 1222 = DSM 20088],3UET_B Crystal structure of alpha-1,3/4-fucosidase from Bifidobacterium longum subsp. infantis D172A/E217A mutant complexed with lacto-N-fucopentaose II [Bifidobacterium longum subsp. infantis ATCC 15697 = JCM 1222 = DSM 20088]

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

Putative alpha-L-fucosidase 1 OS=Oryza sativa subsp. japonica OX=39947 GN=Os04g0560400 PE=3 SV=2

Beta-hexosaminidase Amuc_0868 OS=Akkermansia muciniphila (strain ATCC BAA-835 / DSM 22959 / JCM 33894 / BCRC 81048 / CCUG 64013 / CIP 107961 / Muc) OX=349741 GN=Amuc_0868 PE=1 SV=1

Alpha-L-fucosidase 1 OS=Arabidopsis thaliana OX=3702 GN=FUC1 PE=1 SV=2

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