2FF2:
reference: Transition-state Complex of the Purine-specific Nucleoside Hydrolase of T.vivax: Enzyme Conformational Changes and Implications for Catalysis., Versees W, Barlow J, Steyaert J, J Mol Biol. 2006 Jun 2;359(2):331-46. Epub 2006 Mar 29. PMID: 16630632

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