4LQI:
reference: Omuralide and Vibralactone: Differences in the Proteasome- beta-Lactone-gamma-Lactam Binding Scaffold Alter Target Preferences., List A, Zeiler E, Gallastegui N, Rusch M, Hedberg C, Sieber SA, Groll M, Angew Chem Int Ed Engl. 2013 Nov 28. doi: 10.1002/anie.201308567. PMID: 24285701

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