6NX0:
reference: A widely distributed diheme enzyme from Burkholderia that displays an atypically stable bis-Fe(IV) state., Rizzolo K, Cohen SE, Weitz AC, Lopez Munoz MM, Hendrich MP, Drennan CL, Elliott SJ, Nat Commun. 2019 Mar 7;10(1):1101. doi: 10.1038/s41467-019-09020-4. PMID: 30846684

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