4RIU:
reference: Saccharin: A lead compound for structure-based drug design of carbonic anhydrase IX inhibitors., Mahon BP, Hendon AM, Driscoll JM, Rankin GM, Poulsen SA, Supuran CT, McKenna R, Bioorg Med Chem. 2015 Feb 15;23(4):849-54. doi: 10.1016/j.bmc.2014.12.030. Epub, 2014 Dec 23. PMID: 25614109

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