Iron-sulfur proteins are essential in numerous biological processes, including energy metabolism, DNA synthesis, and DNA repair. They are also involved in photosynthesis and the regulation of gene expression. The term "iron-sulfur protein" refers to a class of proteins that contain iron atoms coordinated to inorganic sulfur atoms. However, there are several other terms used synonymously with iron-sulfur proteins, such as Fe-S proteins, iron-sulfur clusters, iron-sulfur enzymes, and ferredoxins. These terms describe the different types of proteins that contain iron-sulfur clusters. While the functions and structures of these proteins differ, they share a common feature of containing iron-sulfur clusters, which are important for their biological activity.