<p>These conserved proteins from Gram-positive bacteria possess most of the motifs characteristic of a variety ofenzymatically active phosphoesterases [<cite idref="PUB00014394"/>], including acid and alkaline phosphatases,phosphoprotein phosphatases, 5'-nucleotidase, bis(5'-nucleosyl)-tetraphosphatase (symmetrical), sphingomyelinphosphodiesterase, 2',3'-cylic-nucleotide 2'-phosphodiesterase, and 3',5'-nucleotide phosphodiesterase CpdA.Interestingly, the catalytically active histidine usually found has been replaced by asparagine in theseproteins, so their catalytic activity is speculative.</p>