cd04901

C-terminal ACT (regulatory) domain of D-3-Phosphoglycerate Dehydrogenase (3PGDH) found in fungi and bacteria; The C-terminal ACT (regulatory) domain of D-3-Phosphoglycerate Dehydrogenase (3PGDH) found in fungi and bacteria. 3PGDH is an enzyme that belongs to the D-isomer specific, 2-hydroxyacid dehydrogenase family and catalyzes the oxidation of D-3-phosphoglycerate to 3- phosphohydroxypyruvate, which is the first step in the biosynthesis of L-serine, using NAD+ as the oxidizing agent. In Escherichia coli, the SerA 3PGDH is feedback-controlled by the end product L-serine in an allosteric manner. In the homotetrameric enzyme, the interface at adjacent ACT (regulatory) domains couples to create an extended beta-sheet. Each regulatory interface forms two serine-binding sites. The mechanism by which serine transmits inhibition to the active site is postulated to involve the tethering of the regulatory domains together to create a rigid quaternary structure with a solvent-exposed active site cleft. Members of this CD belong to the superfamily of ACT regulatory domains.