5VHF:
reference: Conformational Landscape of the p28-Bound Human Proteasome Regulatory Particle., Lu Y, Wu J, Dong Y, Chen S, Sun S, Ma YB, Ouyang Q, Finley D, Kirschner MW, Mao Y, Mol Cell. 2017 Jul 20;67(2):322-333.e6. doi: 10.1016/j.molcel.2017.06.007. Epub, 2017 Jul 6. PMID: 28689658

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