5FFQ:
reference: Radical new paradigm for heme degradation in Escherichia coli O157:H7., LaMattina JW, Nix DB, Lanzilotta WN, Proc Natl Acad Sci U S A. 2016 Oct 25;113(43):12138-12143. Epub 2016 Oct 10. PMID: 27791000

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