5OJB:
reference: A Noncanonical Proximal Heme Ligand Affords an Efficient Peroxidase in a Globin Fold., Pott M, Hayashi T, Mori T, Mittl PRE, Green AP, Hilvert D, J Am Chem Soc. 2018 Jan 19. doi: 10.1021/jacs.7b12621. PMID: 29309143

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