3CYX:
reference: Effect of flap mutations on structure of HIV-1 protease and inhibition by saquinavir and darunavir., Liu F, Kovalevsky AY, Tie Y, Ghosh AK, Harrison RW, Weber IT, J Mol Biol. 2008 Aug 1;381(1):102-15. Epub 2008 Jul 1. PMID: 18597780

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