3RGW:
reference: The crystal structure of an oxygen-tolerant hydrogenase uncovers a novel iron-sulphur centre., Fritsch J, Scheerer P, Frielingsdorf S, Kroschinsky S, Friedrich B, Lenz O, Spahn CM, Nature. 2011 Oct 16;479(7372):249-52. doi: 10.1038/nature10505. PMID: 22002606

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