1FRV:
reference: Crystal structure of the nickel-iron hydrogenase from Desulfovibrio gigas., Volbeda A, Charon MH, Piras C, Hatchikian EC, Frey M, Fontecilla-Camps JC, Nature 1995 Feb 16;373(6515):580-7. PMID: 7854413

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