6HU9:
reference: Structure of yeast cytochrome c oxidase in a supercomplex with cytochrome bc1., Hartley AM, Lukoyanova N, Zhang Y, Cabrera-Orefice A, Arnold S, Meunier B, Pinotsis N, Marechal A, Nat Struct Mol Biol. 2019 Jan;26(1):78-83. doi: 10.1038/s41594-018-0172-z. Epub, 2018 Dec 31. PMID: 30598554

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