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.

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.

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

F5/8 type C domain. This domain is also known as the discoidin (DS) domain family.

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.

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

CpGH89CBM32-5,from Clostridium perfringens, in complex with galactose [Clostridium perfringens],4A44_A CpGH89CBM32-5, from Clostridium perfringens, in complex with the Tn Antigen [Clostridium perfringens],4A45_A CpGH89CBM32-5, from Clostridium perfringens, in complex with GalNAc- beta-1,3-galactose [Clostridium perfringens],4AAX_A CpGH89CBM32-5, from Clostridium perfringens, in complex with N- acetylgalactosamine [Clostridium perfringens]

Thestructure of the family 32 CBM from C. perfringens NanJ in complex with galactose [Clostridium perfringens]

Characterizationof a Family 32 CBM [Clostridium perfringens]

Structureof CBM32 from Clostridium perfringens beta-N- acetylhexosaminidase GH84C in complex with galactose [Clostridium perfringens ATCC 13124],2J1E_A High Resolution Crystal Structure of CBM32 from a N-acetyl-beta- hexosaminidase in complex with lacNAc [Clostridium perfringens ATCC 13124]

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

A type blood N-acetyl-alpha-D-galactosamine deacetylase OS=Flavonifractor plautii OX=292800 PE=1 SV=1

O-GlcNAcase NagJ OS=Clostridium perfringens (strain ATCC 13124 / DSM 756 / JCM 1290 / NCIMB 6125 / NCTC 8237 / Type A) OX=195103 GN=nagJ PE=1 SV=1

O-GlcNAcase NagJ OS=Clostridium perfringens (strain 13 / Type A) OX=195102 GN=nagJ PE=1 SV=1

Sialidase OS=Clostridium septicum OX=1504 PE=3 SV=1