Frataxin (gene FRDA) [1] is a mitochondrial protein, which is involved in Friedreich's ataxia (FA), an autosomal recessive, progressive degenerative disease characterized by neurodegeneration, cardiomyopathy and diabetes mellitus. Frataxin defect causes mitochondrial iron accumulation, which could lead to specific deficiency in the activities of aconitases and of mitochondrial iron-sulfur dependent enzymes, as suggested by biochemical data [2].

From the X-ray structure of human frataxin [3], it seems that some of the conserved residues are involved in binding one iron atom.

Frataxin is evolutionary related to the following proteins:

• Yeast YFH1 [4], a protein that seems to be involved in the regulation of mitochondrial iron efflux.
• Bacterial cyaY proteins of unknown function. Inactivation of the protein in E.coli has no visible phenotype [5].

As a signature pattern, we selected a conserved region in the central section of these proteins. We also developed a profile that covers the whole conserved region.