2KR4:
reference: Structural and functional characterization of the monomeric U-box domain from E4B., Nordquist KA, Dimitrova YN, Brzovic PS, Ridenour WB, Munro KA, Soss SE, Caprioli RM, Klevit RE, Chazin WJ, Biochemistry. 2010 Jan 19;49(2):347-55. PMID: 20017557

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