1Z53:
reference: The 1.13-A structure of iron-free cytochrome c peroxidase., Bhaskar B, Poulos TL, J Biol Inorg Chem 2005 Jun;10(4):425-30. Epub 2005 May 18. PMID: 15900441

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