1H9X:
reference: The Structure of an alternative form of Paracoccus pantotrophus cytochrome cd(1) nitrite reductase., Sjogren T, Hajdu J, J Biol Chem 2001 Aug 3;276(31):29450-5. PMID: 11373294

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