3AN1:
reference: Crystal Structures of Urate Bound Form of Xanthine Oxidoreductase: Substrate Orientation and Structure of the Key Reaction Intermediate., Okamoto K, Kawaguchi Y, Eger BT, Pai EF, Nishino T, J Am Chem Soc. 2010 Nov 15. PMID: 21077683

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