iron-sulfur cluster

A unit comprising two or more iron atoms and bridging sulfur ligands in an iron-sulfur protein. The recommended designation of a cluster consists of the iron and sulfur content, in square brackets, for example, [2Fe-2S], [3Fe-4S]. The possible oxidation levels are indicated by the net charge excluding the ligands, for example [4Fe-4S]²⁺; [4Fe-4S]⁺ or ([4Fe-4S]^2+;1+) cluster