6CPB:
reference: Testing the N-Terminal Velcro Model of CooA Carbon Monoxide Activation., Tripathi S, Poulos TL, Biochemistry. 2018 May 11. doi: 10.1021/acs.biochem.8b00359. PMID: 29708736

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