IIB   20738
INSTITUTO DE INVESTIGACIONES BIOLOGICAS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Characterization of a Nitric Oxide Synthase from a member of plant kingdom, the algae Ostreococcus tauri
Autor/es:
NOELIA FORESI, NATALIA CORREA-ARAGUNDE AND LORENZO LAMATTINA
Lugar:
Foz de Iguazu, Brasil
Reunión:
Congreso; XXXIX Reunião Anual da Sociedade Brasileira de Bioquímica e Biologia Molecular; 2010
Institución organizadora:
Sociedade Brasileira de Bioquímica e Biologia Molecular
Resumen:
The green algae Ostreococcus tauri (Ot), the smallest member of the plant Kingdom. In the genome of Ot it has been identified a gene sharing high similarity with those coding for nitric oxide synthase (NOS) of mammals. NOS enzymes generate nitric oxide (NO) from arginine using NADPH as electron donor. NO is involved in many physiological processes and associated with responses to (a)biotic stresses in organisms from all Kingdoms. To date, no gene sequence, cDNA or protein coding for a putative plant NOS have been found. In this study, we have conducted the cloning, expression and biochemical characterization of OtNOS. The OtNOS has been successfully expressed as a recombiant protein in Escherichia coli. Activity of the recombinant OtNOS was determined by two methods hemoglobin capture and  NADPH oxidation. Bacteria expressing the recombinant OtNOS display high levels of NO after supplementation with the NOS substrate L-arginine and were more resistant than wt to the oxidant hydrogen peroxide. O. tauri cell culture in exponential growth display NOS activity upon arginine addition and drops during stationary phase. The results in O. tauri also suggest a link between NOS activity and light irradiance. All together, these results describe for the first time the presence of NOS in plant Kingdom.