6YUA:
reference: Gas channel rerouting in a primordial enzyme: Structural insights of the carbon-monoxide dehydrogenase/acetyl-CoA synthase complex from the acetogen Clostridium autoethanogenum., Lemaire ON, Wagner T, Biochim Biophys Acta Bioenerg. 2020 Oct 17;1862(1):148330. doi:, 10.1016/j.bbabio.2020.148330. PMID: 33080205

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