1TBE:
reference: Structure of tetraubiquitin shows how multiubiquitin chains can be formed., Cook WJ, Jeffrey LC, Kasperek E, Pickart CM, J Mol Biol 1994 Feb 18;236(2):601-9. PMID: 8107144

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