Putative catalytic domain of uncharacterized prokaryotic polysaccharide deacetylases similar to bacterial PuuE allantoinases
The family includes a group of uncharacterized prokaryotic polysaccharide deacetylases (DCAs) that show high sequence similarity to the catalytic domain of bacterial PuuE (purine utilization E) allantoinases. PuuE allantoinase specifically catalyzes the hydrolysis of (S)-allantoin into allantoic acid. It functions as a homotetramer. Its monomer is composed of a 7-stranded barrel with detectable sequence similarity to the 6-stranded barrel NodB homology domain of DCA-like proteins in the CE4 superfamily, which removes N-linked or O-linked acetyl groups from cell wall polysaccharides. PuuE allantoinase appears to be metal-independent and acts on a small substrate molecule, which is distinct from the common feature of DCAs which are normally metal ion dependent and recognize multimeric substrates.
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