The cell's cookbook for iron--sulfur clusters: recipes for fool's gold?

Iron±sulfur (Fe S) proteins are present in all forms of life and perform essential roles in, for example, respiration, photosynthesis, and nitrogen fixation. They contain prosthetic groups of complexed iron and TMacid-labile∫ sulfide. These Fe S clusters were identified about 40 years ago; however, it was not until the late 1990s that biosynthetic routes for in vivo assembly started to emerge. The last few years have seen great strides in our knowledge of the proteins involved in Fe S cluster assembly, the core biochemical mechanism, and the specific features of the biosynthesis pathway in eukaryotes. This review will focus on what has been learned so far from Fe S protein biogenesis in baker's yeast, a model organism for higher eukaryotes. Certain aspects of this topic have been discussed in more detail in recent reviews: comparison of Fe S cluster assembly in bacteria and eukaryotes, the role of chaperones in Fe S cluster biogenesis, and a pathological perspective. The most common Fe S clusters found in nature are the rhombic [2Fe 2S] and the cubane [4Fe 4S] clusters (Figure 1).