6ELQ:
reference: CODH-IV: A High-Efficiency CO-Scavenging CO Dehydrogenase with Resistance to O2., Domnik L, Merrouch M, Goetzl S, Jeoung JH, Leger C, Dementin S, Fourmond V, Dobbek H, Angew Chem Int Ed Engl. 2017 Nov 27;56(48):15466-15469. doi:, 10.1002/anie.201709261. Epub 2017 Nov 2. PMID: 29024326

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