A Highly Conserved Iron-Sulfur Cluster Assembly Machinery between Humans and Amoeba Dictyostelium discoideum: The Characterization of Frataxin

OLMOS, JUSTO; PIGNATARO, MARÍA FLORENCIA; BENITEZ DOS SANTOS, ANA BELÉN; BRINGAS, MAURO; KLINKE, SEBASTIÁN; KAMENETZKY, LAURA; VELAZQUEZ, FRANCISCO; SANTOS, JAVIER

Jornada; Primeras jornadas virtuales de la Sociedad Argentina de Biofísica; 2020

Sociedad Argentina de Biofísica

AbstractOn the Highly Conserved Iron-Sulfur Cluster Assembly MachineryNumerous metabolic pathways depend on iron-sulfur clusters ([Fe-S]). We have exploredthe D. discoideum genome looking for genes corresponding to proteins that form themolecular machinery for Fe-S cluster biosynthesis. Based on the structure of themammalian supercomplex and sequence conservation profiles, we inferred the fullfunctionality of the amoeba machinery. In addition, we produced D. discoideum frataxinprotein (DdFXN), the kinetic activator of this pathway. DdFXN is monomeric and compact.The secondary structure content calculated using the far-UV CD spectra was compatiblewith the data expected for the FXN fold. The near-UV CD spectra were compatible withthe corresponding to a folded protein. On the other hand, DdFXN is less stable than thatof human FXN. Based on structural models of DdFXN, we studied key residues involved inthe interaction of DdFXN with the supercomplex and the effect of point mutations on theenergetics. More than 10 residues involved in Friedreich is Ataxia are conserved betweenthe human and DdFXN forms, and a good correlation between the mutational effect onthe energetics of both proteins was inferred, suggesting the existence of similarsequence/stability/function relationships. This information was integrated into anevolutionary context.AcknowldegmentsWe thank F.A.R.A., ANPCyT, CONICET, and UBA for financial support.