Structural and functional Studies of Na-FAR-1 a Novel Fatty Acid and Retinol Binding Protein from Necator Americanus

M.FLORENCIA REY; EDUARDO DE GERÓNIMO; MARINA IBÁÑEZ; MALCOLM W. KENNEDY; ALAN COOPER; BRIAN O. SMITH; BETINA CÓRSICO

Tucumán, Argentina.

Congreso; 45th Annual Meeting-Argentine Society for Biochemistry and Molecular Biology Research; 2009

FARs are a novel class of Fatty Acid and Retinol binding proteins with a structure that has no known counterpart. The majority of retinol binding proteins described to date are beta-strand rich proteins while FARs are mainly alpha-helical. These proteins, which are confined to Nematodes, are secreted by the parasites into the surrounding tissues of the host, playing a central role in the establishment of the infection and making them candidate drug targets for antihelmintic control. Among the genes expressed by adult N. americanus, a FAR protein, Na-FAR-1, has been identified. N.americanus is a blood feeding nematode which causes anemia and growth stunt infecting aboriginal communities in the north of Argentina. We have optimized the purification conditions to obtain rNA-FAR-1 for NMR structural studies and functional ligand binding assays. Circular dichroism has confirmed a high content of alpha-helix. High quality NMR data have been obtained and full structure determination is in progress. Characterization of ligand-bound states have shown evidence of conformational changes. We have also analyzed the ligand binding capacity of Na-FAR-1 by fluorescence confirming that the protein binds retinol, oleic acid and DAUDA with high affinity. The results of the present work constitute a first step in the understanding of the biological function of the protein within the parasite.