4DJO:
reference: Design, Synthesis, and Biological and Structural Evaluations of Novel HIV-1 Protease Inhibitors To Combat Drug Resistance., Parai MK, Huggins DJ, Cao H, Nalam MN, Ali A, Schiffer CA, Tidor B, Rana TM, J Med Chem. 2012 Jul 26;55(14):6328-41. Epub 2012 Jul 13. PMID: 22708897

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