4G4S:
reference: Structure of a Proteasome-Pba1-Pba2 Complex: Implications for Proteasome Assembly, Activation, and Biological Function., Stadtmueller BM, Kish-Trier E, Ferrell K, Petersen CN, Robinson H, Myszka DG, Eckert DM, Formosa T, Hill CP, J Biol Chem. 2012 Aug 28. PMID: 22930756

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