3S2X:
reference: Insights into the Mechanistic Role of the [Fe(4) S(4) ] Cubane in the A-Cluster {[Fe(4) S(4) ]-(SR)-[Ni(p) Ni(d) ]} of Acetyl-Coenzyme A Synthase., Liu Y, Wang F, Li P, Tan X, Chembiochem. 2011 Jun 14;12(9):1417-21. doi: 10.1002/cbic.201100101. Epub, 2011 May 27. PMID: 21626638

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