3RTR:
reference: A RING E3-substrate complex poised for ubiquitin-like protein transfer: structural insights into cullin-RING ligases., Calabrese MF, Scott DC, Duda DM, Grace CR, Kurinov I, Kriwacki RW, Schulman BA, Nat Struct Mol Biol. 2011 Jul 17;18(8):947-9. doi: 10.1038/nsmb.2086. PMID: 21765416

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