Catalytic NodB homology domain of rhizobial NodB-like proteins. This family belongs to the large and functionally diverse carbohydrate esterase 4 (CE4) superfamily, whose members show strong sequence similarity with some variability due to their distinct carbohydrate substrates. It includes many rhizobial NodB chitooligosaccharide N-deacetylase (EC 3.5.1.-)-like proteins, mainly from bacteria and eukaryotes, such as chitin deacetylases (EC 3.5.1.41), bacterial peptidoglycan N-acetylglucosamine deacetylases (EC 3.5.1.-), and acetylxylan esterases (EC 3.1.1.72), which catalyze the N- or O-deacetylation of substrates such as acetylated chitin, peptidoglycan, and acetylated xylan. All members of this family contain a catalytic NodB homology domain with the same overall topology and a deformed (beta/alpha)8 barrel fold with 6- or 7 strands. Their catalytic activity is dependent on the presence of a divalent cation, preferably cobalt or zinc, and they employ a conserved His-His-Asp zinc-binding triad closely associated with the conserved catalytic base (aspartic acid) and acid (histidine) to carry out acid/base catalysis. Several family members show diversity both in metal ion specificities and in the residues that coordinate the metal.

Catalytic NodB homology domain of Streptococcus mutans polysaccharide deacetylase PgdA, Bacillus subtilis YheN, and similar proteins. This family is represented by a putative polysaccharide deacetylase PgdA from the oral pathogen Streptococcus mutans (SmPgdA) and Bacillus subtilis YheN (BsYheN), which are members of the carbohydrate esterase 4 (CE4) superfamily. SmPgdA is an extracellular metal-dependent polysaccharide deacetylase with a typical CE4 fold, with metal bound to a His-His-Asp triad. It possesses de-N-acetylase activity toward a hexamer of chitooligosaccharide N-acetylglucosamine, but not shorter chitooligosaccharides or a synthetic peptidoglycan tetrasaccharide. SmPgdA plays a role in tuning cell surface properties and in interactions with (salivary) agglutinin, an essential component of the innate immune system, most likely through deacetylation of an as-yet-unidentified polysaccharide. SmPgdA shows significant homology to the catalytic domains of peptidoglycan deacetylases from Streptococcus pneumoniae (SpPgdA) and Listeria monocytogenes (LmPgdA), both of which are involved in the bacterial defense mechanism against human mucosal lysozyme. The Bacillus subtilis genome contains six polysaccharide deacetylase gene homologs: pdaA, pdaB (previously known as ybaN), yheN, yjeA, yxkH and ylxY. The biological function of BsYheN is still unknown. This family also includes many uncharacterized polysaccharide deacetylases mainly found in bacteria.

Peptidoglycan/xylan/chitin deacetylase, PgdA/CDA1 family [Carbohydrate transport and metabolism, Cell wall/membrane/envelope biogenesis].

Catalytic NodB homology domain of Clostridium thermocellum acetylxylan esterase and its bacterial homologs. This family is represented by Clostridium thermocellum acetylxylan esterase (CtAXE, EC 3.1.1.72), a member of the carbohydrate esterase 4 (CE4) superfamily. CtAXE deacetylates O-acetylated xylan, a key component of plant cell walls. It shows no detectable activity on generic esterase substrates including para-nitrophenyl acetate. It is specific for sugar-based substrates and will precipitate acetylxylan, as a consequence of deacetylation. CtAXE is a monomeric protein containing a catalytic NodB homology domain with the same overall topology and a deformed (beta/alpha)8 barrel fold as other CE4 esterases. However, due to differences in the topography of the substrate-binding groove, the chemistry of the active center, and metal ion coordination, CtAXE has different metal ion preference and lacks activity on N-acetyl substrates. It is significantly activated by Co2+. Moreover, CtAXE displays distinctly different ligand coordination to the metal ion, utilizing an aspartate, a histidine, and four water molecules, as opposed to the conserved His-His-Asp zinc-binding triad of other CE4 esterases.

Polysaccharide deacetylase. This domain is found in polysaccharide deacetylase. This family of polysaccharide deacetylases includes NodB (nodulation protein B from Rhizobium) which is a chitooligosaccharide deacetylase. It also includes chitin deacetylase from yeast, and endoxylanases which hydrolyzes glucosidic bonds in xylan.

Structureof a family 4 carbohydrate esterase from Bacillus anthracis [Bacillus anthracis str. Ames]

Crystalstructure of the polysaccharide deacetylase Bc1974 from Bacillus cereus in complex with (E)-N-hydroxy-3-(naphthalen-1-yl)prop-2-enamide [Bacillus cereus]

Crystalstructure of the polysaccharide deacetylase Bc1974 from Bacillus cereus [Bacillus cereus],5N1J_B Crystal structure of the polysaccharide deacetylase Bc1974 from Bacillus cereus [Bacillus cereus],5N1J_C Crystal structure of the polysaccharide deacetylase Bc1974 from Bacillus cereus [Bacillus cereus],5N1J_D Crystal structure of the polysaccharide deacetylase Bc1974 from Bacillus cereus [Bacillus cereus],5N1P_A Crystal structure of the polysaccharide deacetylase Bc1974 from Bacillus cereus in complex with N-hydroxynaphthalene-1-carboxamide [Bacillus cereus],5N1P_B Crystal structure of the polysaccharide deacetylase Bc1974 from Bacillus cereus in complex with N-hydroxynaphthalene-1-carboxamide [Bacillus cereus],5N1P_C Crystal structure of the polysaccharide deacetylase Bc1974 from Bacillus cereus in complex with N-hydroxynaphthalene-1-carboxamide [Bacillus cereus],5N1P_D Crystal structure of the polysaccharide deacetylase Bc1974 from Bacillus cereus in complex with N-hydroxynaphthalene-1-carboxamide [Bacillus cereus]

Crystalstructure of the polysaccharide deacetylase Bc1974 from Bacillus cereus in complex with (2S)-2,6-diamino-N-hydroxyhexanamide [Bacillus cereus ATCC 14579],5NC9_B Crystal structure of the polysaccharide deacetylase Bc1974 from Bacillus cereus in complex with (2S)-2,6-diamino-N-hydroxyhexanamide [Bacillus cereus ATCC 14579],5NC9_C Crystal structure of the polysaccharide deacetylase Bc1974 from Bacillus cereus in complex with (2S)-2,6-diamino-N-hydroxyhexanamide [Bacillus cereus ATCC 14579],5NC9_D Crystal structure of the polysaccharide deacetylase Bc1974 from Bacillus cereus in complex with (2S)-2,6-diamino-N-hydroxyhexanamide [Bacillus cereus ATCC 14579],5NCD_A Crystal structure of the polysaccharide deacetylase Bc1974 from Bacillus cereus in complex with (2S)-2-amino-5-(diaminomethylideneamino)-N-hydroxypentanamide [Bacillus cereus],5NCD_B Crystal structure of the polysaccharide deacetylase Bc1974 from Bacillus cereus in complex with (2S)-2-amino-5-(diaminomethylideneamino)-N-hydroxypentanamide [Bacillus cereus],5NCD_C Crystal structure of the polysaccharide deacetylase Bc1974 from Bacillus cereus in complex with (2S)-2-amino-5-(diaminomethylideneamino)-N-hydroxypentanamide [Bacillus cereus],5NCD_D Crystal structure of the polysaccharide deacetylase Bc1974 from Bacillus cereus in complex with (2S)-2-amino-5-(diaminomethylideneamino)-N-hydroxypentanamide [Bacillus cereus],5NEK_A Crystal structure of the polysaccharide deacetylase Bc1974 from Bacillus cereus in complex with acetazolamide [Bacillus cereus],5NEK_B Crystal structure of the polysaccharide deacetylase Bc1974 from Bacillus cereus in complex with acetazolamide [Bacillus cereus],5NEK_C Crystal structure of the polysaccharide deacetylase Bc1974 from Bacillus cereus in complex with acetazolamide [Bacillus cereus],5NEK_D Crystal structure of the polysaccharide deacetylase Bc1974 from Bacillus cereus in complex with acetazolamide [Bacillus cereus],5NEL_A Crystal structure of the polysaccharide deacetylase Bc1974 from Bacillus cereus in complex with ThiametG [Bacillus cereus],5NEL_B Crystal structure of the polysaccharide deacetylase Bc1974 from Bacillus cereus in complex with ThiametG [Bacillus cereus],5NEL_C Crystal structure of the polysaccharide deacetylase Bc1974 from Bacillus cereus in complex with ThiametG [Bacillus cereus],5NEL_D Crystal structure of the polysaccharide deacetylase Bc1974 from Bacillus cereus in complex with ThiametG [Bacillus cereus]

Crystalstructure of the Bc1960 peptidoglycan N-acetylglucosamine deacetylase in complex with 4-naphthalen-1-yl-~{N}-oxidanyl-benzamide [Bacillus cereus ATCC 14579]

Peptidoglycan-N-acetylglucosamine deacetylase BC_1974 OS=Bacillus cereus (strain ATCC 14579 / DSM 31 / CCUG 7414 / JCM 2152 / NBRC 15305 / NCIMB 9373 / NCTC 2599 / NRRL B-3711) OX=226900 GN=BC_1974 PE=1 SV=1

Peptidoglycan-N-acetylglucosamine deacetylase BC_1960 OS=Bacillus cereus (strain ATCC 14579 / DSM 31 / CCUG 7414 / JCM 2152 / NBRC 15305 / NCIMB 9373 / NCTC 2599 / NRRL B-3711) OX=226900 GN=BC_1960 PE=1 SV=1

Peptidoglycan-N-acetylglucosamine deacetylase BC_3618 OS=Bacillus cereus (strain ATCC 14579 / DSM 31 / CCUG 7414 / JCM 2152 / NBRC 15305 / NCIMB 9373 / NCTC 2599 / NRRL B-3711) OX=226900 GN=BC_3618 PE=1 SV=1

Peptidoglycan-N-acetylmuramic acid deacetylase PdaA OS=Bacillus subtilis (strain 168) OX=224308 GN=pdaA PE=1 SV=1

Putative polysaccharide deacetylase YheN OS=Bacillus subtilis (strain 168) OX=224308 GN=yheN PE=3 SV=1