The competition between chemistry and biology in assembling iron–sulfur derivatives. Molecular structures and electrochemistry. Part III. {[Fe2S2](Cys)3(X)} (X = Asp, Arg, His) and {[Fe2S2](Cys)2(His)2} proteins

• We illustrate structure and electrochemistry of proteins containing {[Fe2S2](Cys)3(X)} and {[Fe2S2](Cys)2(His)2}core(s).
• We present the structural changes consequent to the Fe(III)/Fe(III)/Fe(III)Fe(II) passage in proteins harboring {[Fe2S2](Cys)3(X)} and {[Fe2S2](Cys)2(His)2} redox active centers.
• We examine structure/electrochemistry of synthetic {[Fe2S2](S-X)2(N-X’)2} complexes biomimetic of {[Fe2S2](Cys)2(His)2}fragments.

Iron–sulfur clusters are ubiquitous and evolutionary ancient prosthetic groups which participate in crucial electron transfer processes. Just in view of such a significant aspect we planned to update their structure and electrochemistry. In this picture, after having reviewed {Fe(Cys)4} rubredoxins (Coord. Chem. Rev., 257 (2013) 1777–1805) and {[Fe2S2](Cys)4} ferredoxins (Coord. Chem. Rev., 280 (2103) 50–83), we will now deal with Rieske proteins (which have {[Fe2S2](Cys)2(His)2} clusters as redox active center), also discussing about proteins having {[Fe2S2](Cys)3(X)} (X = Asp, Arg, His) redox active centers, which can be considered as intermediates between classical {[Fe2S2](Cys)4} (hereafter [2Fe-2S]) and Rieske proteins (hereafter [2Fe-2S]R). As usual, we will also deal with the synthetic analogues of the iron–sulfur clusters of Rieske proteins.

Protein film voltammetric responses of “high-potential Rieske proteins” (top) and “low-potential Rieske proteins” (bottom).Figure optionsDownload high-quality image (143 K)Download as PowerPoint slide