Chime Text

Ribbon representation of D-3-phosphoglycerate dehydrogenase depicts the quartnary structure. (Subunit A=blue, Subunit B=cyan, Subunit C=yellow, Subunit D=green).

Each subunit of this tetrameric enzyme contains three domains. The regulatory domain (yellow), consists of residues 336-410, the substrate binding domain (blue), contains residues 7-107 and 295-335, and the nucleotide binding domain (red), is made up of residues 108-294. The overall structure resembles a twisted donut-like shape with two distinct contacts between subunits: i) between adjacent regulatory domains, and ii) between nucleotide binding domains.

The structural similarities of three members of the D-2-hydroxyacid dehydrogenase family: D-glycerate dehydrogenase, formate dehydrogenase, and D-3-phosphoglycerate dehydrogenase, led to the hypothesis that the deletion of the regulatory domain in PGDH would not destroy the activity of the enzyme.