Non-viral sialidases. Sialidases or neuraminidases function to bind and hydrolyze terminal sialic acid residues from various glycoconjugates, they play vital roles in pathogenesis, bacterial nutrition and cellular interactions. They have a six-bladed, beta-propeller fold with the non-viral sialidases containing 2-5 Asp-box motifs (most commonly Ser/Thr-X-Asp-[X]-Gly-X-Thr- Trp/Phe). This CD includes eubacterial and eukaryotic sialidases.

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.

NPCBM/NEW2 domain. This novel putative carbohydrate binding module (NPCBM) domain is found at the N-terminus of glycosyl hydrolase family 98 proteins. This domain has also been called the NEW2 domain (Naumoff DG. Phylogenetic analysis of alpha-galactosidases of the GH27 family. Molecular Biology (Engl Transl). (2004)38:388-399.)

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

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.

Lacto-N-biosidasefrom Bifidobacterium bifidum [Bifidobacterium bifidum JCM 1254],4H04_B Lacto-N-biosidase from Bifidobacterium bifidum [Bifidobacterium bifidum JCM 1254],4JAW_A Crystal Structure of Lacto-N-Biosidase from Bifidobacterium bifidum complexed with LNB-thiazoline [Bifidobacterium bifidum JCM 1254],4JAW_B Crystal Structure of Lacto-N-Biosidase from Bifidobacterium bifidum complexed with LNB-thiazoline [Bifidobacterium bifidum JCM 1254],5BXP_A LNBase in complex with LNB-LOGNAc [Bifidobacterium bifidum JCM 1254],5BXP_B LNBase in complex with LNB-LOGNAc [Bifidobacterium bifidum JCM 1254],5BXR_A LNBase in complex with LNB-NHAcDNJ [Bifidobacterium bifidum JCM 1254],5BXR_B LNBase in complex with LNB-NHAcDNJ [Bifidobacterium bifidum JCM 1254],5BXS_A LNBase in complex with LNB-NHAcCAS [Bifidobacterium bifidum JCM 1254],5BXS_B LNBase in complex with LNB-NHAcCAS [Bifidobacterium bifidum JCM 1254],5BXT_A LNBase in complex with LNB-NHAcAUS [Bifidobacterium bifidum JCM 1254],5BXT_B LNBase in complex with LNB-NHAcAUS [Bifidobacterium bifidum JCM 1254]

Sialidase,Large 68kd Form, Complexed With Galactose [Micromonospora viridifaciens],1EUU_A Sialidase Or Neuraminidase, Large 68kd Form [Micromonospora viridifaciens]

Mutagenesisof the Nucleophilic Tyrosine in a Bacterial Sialidase to Phenylalanine. [Micromonospora viridifaciens],1WCQ_B Mutagenesis of the Nucleophilic Tyrosine in a Bacterial Sialidase to Phenylalanine. [Micromonospora viridifaciens],1WCQ_C Mutagenesis of the Nucleophilic Tyrosine in a Bacterial Sialidase to Phenylalanine. [Micromonospora viridifaciens]

Galactoserecognition by the carbohydrate-binding module of a bacterial sialidase. [Micromonospora viridifaciens],2BZD_B Galactose recognition by the carbohydrate-binding module of a bacterial sialidase. [Micromonospora viridifaciens],2BZD_C Galactose recognition by the carbohydrate-binding module of a bacterial sialidase. [Micromonospora viridifaciens]

Contributionof the Active Site Aspartic Acid to Catalysis in the Bacterial Neuraminidase from Micromonospora viridifaciens. [Micromonospora viridifaciens],1W8O_A Contribution of the Active Site Aspartic Acid to Catalysis in the Bacterial Neuraminidase from Micromonospora viridifaciens [Micromonospora viridifaciens]

Sialidase OS=Micromonospora viridifaciens OX=1881 GN=nedA PE=1 SV=1

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-N-acetylhexosaminidase OS=Streptococcus pneumoniae serotype 4 (strain ATCC BAA-334 / TIGR4) OX=170187 GN=strH PE=1 SV=2

Putative endo-alpha-N-acetylgalactosaminidase OS=Renibacterium salmoninarum (strain ATCC 33209 / DSM 20767 / JCM 11484 / NBRC 15589 / NCIMB 2235) OX=288705 GN=RSal33209_1326 PE=3 SV=2

Beta-hexosaminidase subunit A1 OS=Dictyostelium discoideum OX=44689 GN=hexa1 PE=1 SV=1