3Q6J:
reference: Structural basis for carbon dioxide binding by 2-ketopropyl coenzyme M oxidoreductase/carboxylase., Pandey AS, Mulder DW, Ensign SA, Peters JW, FEBS Lett. 2011 Feb 4;585(3):459-64. Epub 2010 Dec 27. PMID: 21192936

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