3BC4:
reference: Targeting the open-flap conformation of HIV-1 protease with pyrrolidine-based inhibitors., Bottcher J, Blum A, Dorr S, Heine A, Diederich WE, Klebe G, ChemMedChem. 2008 Sep;3(9):1337-44. PMID: 18720485

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