Putative catalytic NodB homology domain of uncharacterized BH0857 protein from Bacillus halodurans and its bacterial homologs. This family is represented by a putative polysaccharide deacetylase BH0857 from Bacillus halodurans. Although its biological function still remains unknown, BH0857 shows high sequence homology to the catalytic NodB homology domain of Streptococcus pneumoniae polysaccharide deacetylase PgdA (SpPgdA), which is an extracellular metal-dependent polysaccharide deacetylase with de-N-acetylase activity toward a hexamer of chitooligosaccharide N-acetylglucosamine, but not shorter chitooligosaccharides or a synthetic peptidoglycan tetrasaccharide. Both BH0857 and SpPgdA belong to the carbohydrate esterase 4 (CE4) superfamily. This family also includes many uncharacterized bacterial polysaccharide deacetylases.

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.

Putative catalytic NodB homology domain of uncharacterized BH1302 protein from Bacillus halodurans and its bacterial homologs. This family is represented by a putative polysaccharide deacetylase BH1302 from Bacillus halodurans. Although its biological function is unknown, BH1302 shows high sequence homology to the catalytic NodB homology domain of Streptococcus pneumoniae polysaccharide deacetylase PgdA (SpPgdA), which is an extracellular metal-dependent polysaccharide deacetylase with de-N-acetylase activity toward a hexamer of chitooligosaccharide N-acetylglucosamine, but not shorter chitooligosaccharides or a synthetic peptidoglycan tetrasaccharide. Both BH1302 and SpPgdA belong to the carbohydrate esterase 4 (CE4) superfamily. This family also includes many uncharacterized bacterial polysaccharide deacetylases.

Putative catalytic NodB homology domain of Bacillus subtilis putative polysaccharide deacetylase PdaB, 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 the putative polysaccharide deacetylase PdaB encoded by the pdaB gene on sporulation of Bacillus subtilis. Although its biochemical properties remain to be determined, the PdaB (YbaN) protein is essential for maintaining spores after the late stage of sporulation and is highly conserved in spore-forming bacteria. The glycans of the spore cortex may be candidate PdaB substrates. Based on sequence similarity, the family members are classified as carbohydrate esterase 4 (CE4) superfamily members. However, the classical His-His-Asp zinc-binding motif of CE4 esterases is missing in this family.

ChainA, Predicted xylanase/chitin deacetylase [Caldanaerobacter subterraneus subsp. tengcongensis MB4]

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

Crystalstructure of the Xyl-CE4 domain of a multidomain xylanase from the hindgut metagenome of Trinervitermes trinervoides [uncultured bacterium]

ChainA, Glycoside Hydrolase, Family 11:clostridium Cellulosome Enzyme, Dockerin Type I:polysaccharide [Acetivibrio thermocellus],2C79_A Chain A, GLYCOSIDE HYDROLASE, FAMILY 11:CLOSTRIDIUM CELLULOSOME ENZYME, DOCKERIN TYPE I:POLYSACCHARIDE [Acetivibrio thermocellus]

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

Bifunctional xylanase/deacetylase OS=Pseudobutyrivibrio xylanivorans OX=185007 GN=xyn11A PE=1 SV=2