3EIG:
reference: Multiple conformers in active site of human dihydrofolate reductase F31R/Q35E double mutant suggest structural basis for methotrexate resistance., Volpato JP, Yachnin BJ, Blanchet J, Guerrero V, Poulin L, Fossati E, Berghuis AM, Pelletier JN, J Biol Chem. 2009 Jul 24;284(30):20079-89. Epub 2009 May 28. PMID: 19478082

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