4DQB:
reference: Hydrophobic Core Flexibility Modulates Enzyme Activity in HIV-1 Protease., Mittal S, Cai Y, Nalam MN, Bolon DN, Schiffer CA, J Am Chem Soc. 2012 Mar 7;134(9):4163-8. Epub 2012 Feb 28. PMID: 22295904

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