In a recent series of review papers we have updated structure/electrochemistry of metalloproteins harboring single types of iron-sulfur clusters, namely {Fe(Cys)(4)}, {[Fe2S2](Cys)(4)}, {[Fe2S2](Cys)(3)(X)} (X = Asp, Arg, His), {[Fe2S2](Cys)(2)(His)(2)}, {[Fe3S4](Cys)(3)}, {[Fe4S4](Cys)(4)} and {[Fe4S4](S-Cys(gamma))3(nonthiolate ligand)} cores, and their synthetic analogs. We now face with iron-sulfur proteins harboring iron-sulfur centres of different nuclearities. In this picture we start with proteins containing [4Fe-4S] + [2Fe-2S] clusters. (C) 2017 Elsevier Inc. All rights reserved.