1C4A:
reference: Binding of exogenously added carbon monoxide at the active site of the iron-only hydrogenase (CpI) from Clostridium pasteurianum., Lemon BJ, Peters JW, Biochemistry 1999 Oct 5;38(40):12969-73. PMID: 10529166

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