3BY4:
reference: Structural basis for ubiquitin recognition by the Otu1 ovarian tumor domain protein., Messick TE, Russell NS, Iwata AJ, Sarachan KL, Shiekhattar R, Shanks JR, Reyes-Turcu FE, Wilkinson KD, Marmorstein R, J Biol Chem. 2008 Apr 18;283(16):11038-49. Epub 2008 Feb 12. PMID: 18270205

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