2O74:
reference: The structure of 2-oxo-4-hydroxy-4-carboxy-5-ureidoimidazoline decarboxylase provides insights into the mechanism of uric acid degradation., Cendron L, Berni R, Folli C, Ramazzina I, Percudani R, Zanotti G, J Biol Chem. 2007 Jun 22;282(25):18182-9. Epub 2007 Apr 11. PMID: 17428786

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