Expression of NOS from marine microorganisms improves growth and nitrogen metabolism in e. coli

FORESI NOELIA PAMELA; CORREA ARAGUNDE NATALIA; DEL CASTELLO FIORELLA; LAMATTINA LORENZO; NEJAMKIN ANDRES

Cordoba

Congreso; LII Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2016

SAIB

Nitric oxide synthase (NOS) catalyzes the biosynthesis of nitric oxide (NO), a signal molecule in diverse biological processes, through the oxidation of L-arginine. We have characterized the first NOS enzyme from the plant kingdom, belonging to the alga Ostreococcus tauri (OtNOS). Later, we identified a NOS in the cyanobacteria Synechococcus PCC7335 (SyNOS), with an extra N-terminal globin domain. In this work, we studied the SyNOS expression in Synechococcus and analyzed the impact of the heterologous SyNOS expression in E. coli. Synechococcus is able to produce NO and express SyNOS in normal culture conditions. The NO production is inhibited by the addition of the NOS inhibitor L-NAME. E. coli expressing either SyNOS or OtNOS showed an increased growth rate and viability, compared to bacteria transformed with the empty vector (EV). Furthermore, the recombinant bacteria are able to grow in media containing L-Arg as unique nitrogen source. Bacteria expressing SyNOS display higher growth rate, as well as levels of nitrites and nitrates, compared to bacteria expressing OtNOS and EV. The expression of the HMP is indicative of nitrosative stress. HMP is induced in bacteria expressing OtNOS but not SyNOS, suggesting that SyNOS is able to detoxify NO. The mechanism by which SyNOS detoxifies NO and displays higher growing rates is under investigation.