Metal-dependent phosphatase with probable damage-control functions (By similarity). Could hydrolyze oxidatively damaged purine nucleotides or their biosynthetic intermediates (By similarity). Subfamily I proteins are distinguished by three conserved motifs: the CxxC motif localized near the N-terminus, the GNFE motif localized about 40 residues from the C-terminus, and the KC motif localized about 25 residues from the C-terminus (Probable). In the crystal structures of the subfamily I proteins, the side chains of the cysteines in the CxxC and KC motifs face each other across the rim of the putative substrate-binding cleft, and the GNFE motif lies deep in the cleft close to the metal-binding aspartate and asparagine (Probable). the 3 conserved cysteines in motifs CxxC and KC play a key role in the interaction with the Fe-containing chromophore, which is not directly involved in catalysis (Probable). Belongs to the damage-control phosphatase family. Nucleotides phosphatase I subfamily.