3EHB:
reference: A D-pathway mutation decouples the paracoccusdenitrificans cytochrome c oxidase by altering the side-chain orientation of a distant conserved glutamate., Durr KL, Koepke J, Hellwig P, Muller H, Angerer H, Peng G, Olkhova E, Richter OM, Ludwig B, Michel H, J Mol Biol. 2008 Dec 26;384(4):865-77. Epub 2008 Oct 9. PMID: 18930738

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