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 Bacillus subtilis polysaccharide deacetylase PdaA, and its bacterial homologs. The Bacillus subtilis genome contains six polysaccharide deacetylase gene homologs: pdaA, pdaB (previously known as ybaN), yheN, yjeA, yxkH and ylxY. This family is represented by Bacillus subtilis pdaA gene encoding polysaccharide deacetylase BsPdaA, which is a member of the carbohydrate esterase 4 (CE4) superfamily. BsPdaA deacetylates peptidoglycan N-acetylmuramic acid (MurNAc) residues to facilitate the formation of muramic delta-lactam, which is required for recognition of germination lytic enzymes. BsPdaA deficiency leads to the absence of muramic delta-lactam residues in the spore cortex. Like other CE4 esterases, BsPdaA consists of a single catalytic NodB homology domain that appears to adopt a deformed (beta/alpha)8 barrel fold with a putative substrate binding groove harboring the majority of the conserved residues. It utilizes a general acid/base catalytic mechanism involving a tetrahedral transition intermediate, where a water molecule functions as the nucleophile tightly associated to the zinc cofactor.

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.

Putative catalytic NodB homology domain of uncharacterized protein YlxY from Bacillus subtilis and its bacterial homologs. The Bacillus subtilis genome contains six polysaccharide deacetylase gene homologs: pdaA, pdaB (previously known as ybaN), yheN, yjeA, yxkH and ylxY. This family is represented by Bacillus subtilis putative polysaccharide deacetylase BsYlxY, encoded by the ylxY gene, which is a member of the carbohydrate esterase 4 (CE4) superfamily. Although its biological function still remains unknown, BsYlxY shows high sequence homology to the catalytic domain of Bacillus subtilis pdaB gene encoding a putative polysaccharide deacetylase (BsPdaB), which is essential for the maintenance of spores after the late stage of sporulation and is highly conserved in spore-forming bacteria. However, disruption of the ylxY gene in B. subtilis did not cause any sporulation defect. Moreover, the Asp residue in the classical His-His-Asp zinc-binding motif of CE4 esterases is mutated to a Val residue in this family. Other catalytically relevant residues of CE4 esterases are also not conserved, which suggest that members of this family may be inactive.

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

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

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

Crystalstructure of the Bc1960 peptidoglycan N-acetylglucosamine deacetylase in complex with 4-naphthalen-1-yl-~{N}-oxidanyl-benzamide [Bacillus cereus ATCC 14579],5O6Y_C Crystal structure of the Bc1960 peptidoglycan N-acetylglucosamine deacetylase in complex with 4-naphthalen-1-yl-~{N}-oxidanyl-benzamide [Bacillus cereus ATCC 14579],5O6Y_D Crystal structure of the Bc1960 peptidoglycan N-acetylglucosamine deacetylase in complex with 4-naphthalen-1-yl-~{N}-oxidanyl-benzamide [Bacillus cereus ATCC 14579]

Crystalstructure of the Bc1960 peptidoglycan N-acetylglucosamine deacetylase from Bacillus cereus [Bacillus cereus ATCC 14579],4L1G_B Crystal structure of the Bc1960 peptidoglycan N-acetylglucosamine deacetylase from Bacillus cereus [Bacillus cereus ATCC 14579],4L1G_C Crystal structure of the Bc1960 peptidoglycan N-acetylglucosamine deacetylase from Bacillus cereus [Bacillus cereus ATCC 14579],4L1G_D Crystal structure of the Bc1960 peptidoglycan N-acetylglucosamine deacetylase from Bacillus cereus [Bacillus cereus ATCC 14579]

Crystalstructure of a BA3943 mutant,a CE4 family pseudoenzyme with restored enzymatic activity. [Bacillus anthracis]

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

Uncharacterized protein YlxY OS=Bacillus subtilis (strain 168) OX=224308 GN=ylxY PE=3 SV=2

Uncharacterized 30.6 kDa protein in fumA 3'region OS=Geobacillus stearothermophilus OX=1422 PE=3 SV=1

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