3AYX:
reference: Structural basis for a [4Fe-3S] cluster in the oxygen-tolerant membrane-bound [NiFe]-hydrogenase., Shomura Y, Yoon KS, Nishihara H, Higuchi Y, Nature. 2011 Oct 16;479(7372):253-6. doi: 10.1038/nature10504. PMID: 22002607

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