4G7L:
reference: Discrimination between CO and O(2) in Heme Oxygenase: Comparison of Static Structures and Dynamic Conformation Changes following CO Photolysis., Sugishima M, Moffat K, Noguchi M, Biochemistry. 2012 Oct 18. PMID: 23043644

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