2FAK:
reference: Crystal Structures of Salinosporamide A (NPI-0052) and B (NPI-0047) in Complex with the 20S Proteasome Reveal Important Consequences of beta-Lactone Ring Opening and a Mechanism for Irreversible Binding., Groll M, Huber R, Potts BC, J Am Chem Soc. 2006 Apr 19;128(15):5136-5141. PMID: 16608349

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