What are the structural implications for iron binding by frataxin, the mitochondrial protein whose decreased expression results in Friedreich's ataxia? Though frataxin has been shown to be essential for proper handling of iron within mitochondria (e.g. for iron–sulfur cluster and haem biosynthesis), its exact molecular function remains unclear. In this issue of the Biochemical Journal, Correia and colleagues. investigate the relationship between structure and function at the putative iron-binding site of Yfh1 (yeast frataxin).