4Q2K:
reference: Macrocyclic protease inhibitors with reduced Peptide character., Chua KC, Pietsch M, Zhang X, Hautmann S, Chan HY, Bruning JB, Gutschow M, Abell AD, Angew Chem Int Ed Engl. 2014 Jul 21;53(30):7828-31. doi: 10.1002/anie.201404301. , Epub 2014 Jun 5. PMID: 24903745

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