Definition of [2Fe-2S]

Designation of a two-iron, two-labile-sulfur cluster in a protein, comprising two sulfido-bridged iron atoms. The oxidation levels of the clusters are indicated by adding the charges on the iron and sulfide atoms, i.e. [2Fe-2S]2+; [2Fe-2S]+. The alternative designation, which conforms to inorganic chemical convention is to include the charges on the ligands; this is more appropriate where the ligands are other than the usual cysteine sulfurs, such as in the Rieske proteins. See also ferredoxin.