6NN6:
reference: Structural Basis for Recognition of Ubiquitylated Nucleosome by Dot1L Methyltransferase., Anderson CJ, Baird MR, Hsu A, Barbour EH, Koyama Y, Borgnia MJ, McGinty RK, Cell Rep. 2019 Feb 12;26(7):1681-1690.e5. doi: 10.1016/j.celrep.2019.01.058. PMID: 30759380

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