2IWK:
reference: Insight into catalysis of nitrous oxide reductase from high-resolution structures of resting and inhibitor-bound enzyme from Achromobacter cycloclastes., Paraskevopoulos K, Antonyuk SV, Sawers RG, Eady RR, Hasnain SS, J Mol Biol. 2006 Sep 8;362(1):55-65. Epub 2006 Jul 12. PMID: 16904686

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