Putative catalytic domain of Synechocystis sp. Sll1306 protein and other bacterial homologs
The family contains Synechocystis sp. Sll1306 protein and uncharacterized bacterial polysaccharide deacetylases. Although their biological function remains unknown, they show very high sequence homology 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 polysaccharide deacetylase-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 polysaccharide deacetylases that are normally metal ion dependent and recognize multimeric substrates.
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