Chimera of Globin/Nitric Oxide Synthase: Toward Improving Nitric Oxide Homeostasis and Nitrogen Recycling and Availability

DEL CASTELLO, FIORELLA; NEJAMKIN, ANDRÉS; FORESI, NOELIA; LAMATTINA, LORENZO; CORREA-ARAGUNDE, NATALIA

Frontiers in Plant Science

Frontiers

Año: 2020 vol. 11

The interaction of nitric oxide (NO) with globin (Glb) proteins is widely studied in all organisms. Besides oxygen sensing and transport, Glbs have an important role in providing cells NO homeostasis. Glbs detoxifies NO in either aerobic and anaerobic conditions. The characterization of a chimeric enzyme globin/nitric oxide synthase (Glb-NOS) from the cyanobacterium Synechococcus PCC 7335 (SyNOS) opened interesting questions regarding its biological function. The activity of Glb-NOS is a coupled reaction between Glb and NOS leading to the regulation of NO/NO3- release. Results indicate that SyNOS is a genuine NOS that possesses high NO dioxygenase (NOD) activity producing NO3-. In this Opinion we will discuss if this chimeric Glb-NOS is a sophisticated evolution to integrate homeostasis and signaling of NO besides the potential function in nitrogen (N) metabolism. The occurrence of Glb-NOS in organisms will also be addressed. Interestingly, Glbs also associate with the NO-producing enzyme nitrate reductase (NR). NR regulates N assimilation and metabolism in plants. We postulate that the evolution of chimeric Glb-NOS may be contributing to a more efficient N recycling and improving the growth of organisms in N fluctuating conditions.