Ferredoxins Containing One [4Fe–4S] Center

Abstract

AbstractFerredoxins (Fds) are iron–sulfur proteins that function as electron carriers in diverse metabolic pathways. Generally, Fds are acidic proteins with a low molecular weight and have very low redox potentials. Although historically the name of Fd was given to electron carrier proteins containing iron–sulfur clusters in bacteria, plants and algae, and animals, they differ not only in the foldings of the polypeptide chains but also in the structures of the active centers; the canonical bacterial Fds have one or two [4Fe–4S] (or [3Fe–4S]) centers whereas the plant‐type and animal‐type Fds have one [2Fe–2S] cluster. Bacterial Fds are evolutionally related whether they have one or two [4Fe–4S] (or [3Fe–4S]) clusters, but are distinct from high potential iron–sulfur proteins that also have one [4Fe–4S] cluster. Fds containing one [4Fe–4S] cluster, on which this article is focussed, are one of several distinct classes of bacterial Fds with low redox potentials.