1PSD:
reference: The allosteric ligand site in the Vmax-type cooperative enzyme phosphoglycerate dehydrogenase., Schuller DJ, Grant GA, Banaszak LJ, Nat Struct Biol 1995 Jan;2(1):69-76. PMID: 7719856

This OCA Structure page
uses Jmol, developed by the Jmol Development Team (documentation).