<p>Phosphoglycolate phosphatase (PGP) is an essential enzyme in the glycolate salvage pathway in higher organisms (photorespiration in plants). Phosphoglycolate results from the oxidase activity of RubisCO in the Calvin cycle when concentrations of carbon dioxide are low relative to oxygen. In <taxon tax_id="106590">Ralstonia eutropha</taxon> and <taxon tax_id="1063">Rhodobacter sphaeroides</taxon>, the PGP gene (CbbZ) is located on an operon along with other Calvin cycle enzymes including RubisCO [<cite idref="PUB00009585"/>, <cite idref="PUB00009586"/>]. In E. coli, however, there does not appear to be a functional Calvin cycle (RubisCO is absent), although the E. coli PGP gene (gph) is on the same operon (dam) with ribulose-5-phosphate-3-epimerase (rpe), a gene in the pentose-phosphate pathway (along with other, unrelated genes). This enzyme is a member of the Haloacid Dehalogenase (HAD) superfamily of aspartate-nucleophile hydrolase enzymes.</p><p>This entry represents an alpha-helical orthogonal bundle found towards the N terminus of this family of proteins.</p>