1QPU:
reference: The solution structure of oxidized Escherichia coli cytochrome b562., Arnesano F, Banci L, Bertini I, Faraone-Mennella J, Rosato A, Barker PD, Fersht AR, Biochemistry 1999 Jul 6;38(27):8657-70. PMID: 10393541

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