Maize frataxins: a role in iron handling and ROS protection?

BUCHENSKY, C.; GIMENEZ MART E.; ATRIAN, S.; PAGANI, M.A.; BUSI, M. V.; DIEGO FABIAN GOMEZ CASATI

Rosario

Congreso; L Reunión de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB); 2014

SAIB

Iron is essential for many cellular functions but free iron can be toxic at physiological conditions, thus it must be carefully regulated. The highly conserved protein Frataxin (FH), characterized in bacteria, yeast, humans and Arabidopsis thaliana (AtFH), represents a candidate for iron management. FH has been proposed to participate in Fe-S cluster assembly, iron homeostasis, heme metabolism, ROS and REDOX control and protection against oxidative damage. In eukaryotes, FH is nuclear encoded with mitochondrial localization. We identified in maize two coding sequences -ZmFH42 and ZmFH55- homologous to AtFH. Recently, we have been cloned, purified and characterized the iron binding properties of these isoforms by the attenuation of Fenton´s reaction and their capacity to maintain Fe(II) in solution. We have also determined their subcellular localization by fluorescent confocal microscopy, suggesting a dual localization in mitochondria and chloroplast. In this work, we show the self-assembly properties of both recombinant proteins in the presence of iron by nondenaturing PAGE. Besides, we demonstrate their protective role against oxidative damage in Saccharomyces cerevisiae FH knock out cells complementation assays. These preliminary results suggest that ZmFH42 and ZmFH55 may play important roles in protection against oxidative stress and iron homeostasis and bioavailability.