Friedreich's ataxia  is a neurodegenerative disease caused by a decrease in the mitochondrial protein frataxin.  Frataxin, an iron(II) chaperone, delivers the metal to proteins which require iron for their function.  Decreased frataxin levels result in increased free iron within the mitochondria, which through Fenton chemistry promotes oxidative damage to heart and muscle tissue.  Despite many efforts, iron coordination by frataxin is still unclear and the experiments to address it are often contradictory. To give more detailed information about the metal coordination environment, we used copper(II) as a spectroscopic probe for iron(II).  Various spectroscopic techniques including UV-visible, EPR and NMR spectroscopies suggest that frataxin binds two copper ions using at least one imidazole ligand. To further explore the Cu(II) coordination environment, three specific histidine residues were mutated to alanine and the proteins were also characterized spectroscopically. The results from these studies will be presented and discussed.

Using Cu(II) as a spectroscopic probe for metal coordination to Frataxin

240th National Meeting (2010)

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