Protein Domain : NodB homology domain IPR002509

Type	Domain
Description	The NodB homology domain is a catalytic domain of ~200 amino acid residues, which has been named after its similarity to rhizobial NodBchitooligosaccharide deacetylase. It is found in members of carbohydrate esterase family 4 (CE4) and in PuuE proteins.Members of the CE4 family exhibit metal-dependent deacetylation of O- and N- acetylated polysaccharides, such as chitin, peptidoglycan, and acetylxylan.Proteins belonging to this family have conserved residues that are important for metal coordination (D-H-H triad) and enzymatic activity. CE4 enzymestypically require a divalent Zn(2+) or Ni(2+) metal ion that is usually coordinated by an aspartate and two histidine residues [, , , ].PuuE proteins are allantoinases that catalyze the hydrolytic cleavage of the hydantoin ring of allantoin. The conserved D-H-H metal-binding triad isreplaced by E-H-W in PuuE proteins. Amino acid substitutions are also observed for residues that have been implicated in catalysis, conferring metalindependency to the enzyme [ ].The NodB homology domain adopts a deformed (beta/alpha) barrel fold comprising eight parallel β-strands, with the C-terminal ends of five of these strandsforming the solvent-exposed active site region, surrounded by eight alpha- helices [, , ].
Short Name	NODB_dom