Characterization of AtNfs1, a Mitochondrial Cysteine Desulphurase From Arabidopsis

TUROWSKI VALERIA ROSANA; BUSI MARIA VICTORIA; GOMEZ-CASATI DIEGO

Villa Carlos Paz, Córdoba.

Congreso; XLIV Reunión Anual Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB); 2008

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB)

Iron-Sulfur (Fe-S) clusters are ubiquitous prosthetic groups required to sustain fundamental life processes. The assembly of Fe-S clusters requires the coordinated delivery of both iron and sulfide and involves at least ten proteins. The first step in biosynthesis is carried out by cysteine desulfurases (NifS like proteins) which catalyze the formation of elemental sulfur and alanine from cysteine. The Arabidopsis genome encodes two cysteine desulfurases AtNfs1 and AtNfs2. AtNfs2 has been characterized as a plastid protein whereas AtNfs1 has been localized to the mitochondria. In order to characterize this first step in Fe-S cluster biosynthesis in plant mitochondria, we expressed, purified and performed kinetic characterization of the recombinant protein AtNfs1m (lacking the mitochondrial transit peptide). We also examined possible protein interaction of AtNfs1 with the Arabidopsis frataxin homologue, AtFH (a potential donor of iron for the assembly of cluster Fe-S). The results confirmed that AtNfs1m displays cysteine desulfurase activity; moreover, it is possible to speculate that AtFH modulates the activity of AtNfs1