1CCE:
reference: Construction of a bisaquo heme enzyme and binding by exogenous ligands., McRee DE, Jensen GM, Fitzgerald MM, Siegel HA, Goodin DB, Proc Natl Acad Sci U S A 1994 Dec 20;91(26):12847-51. PMID: 7809133

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