3MYR:
reference: The crystal structure of the [NiFe] hydrogenase from the photosynthetic bacterium Allochromatium vinosum: characterization of the oxidized enzyme (Ni-A state)., Ogata H, Kellers P, Lubitz W, J Mol Biol. 2010 Sep 17;402(2):428-44. Epub 2010 Jul 29. PMID: 20673834

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