A New Sensor to Detect Physiological Levels of Nitrate and Nitrite♦

Visualization of NO 3 −/NO 2 − Dynamics in Living Cells by Fluorescence Resonance Energy Transfer (FRET) Imaging Employing a Rhizobial Two-component Regulatory System

♦ See referenced article, J. Biol. Chem. 2016, 291, 2260–2269

Nitric oxide is a critical second messenger in the body, playing roles in vascular homeostasis, neurotransmission, and host defense. The molecule recently was found to be made from two sources in body, nitrate (NO 3 −) and nitrite (NO 2 −). In this Paper of the Week, a team led by Takafumi Uchida at Tohoku University describes a new technique for visualizing the dynamics of nitrate and nitrite. The technique is called sNOOOpy, which stands for “sensor for NO 3 −/NO 2 − in physiology.” sNOOOpy is a genetically encoded intermolecular fluorescence resonance energy transfer (FRET)-based indicator that senses levels of nitrate and nitrite. The investigators demonstrated with in vitro and cell culture studies that sNOOOpy can monitor intracellular levels in the micromolar range of nitrate and nitrite in real time. The authors say, “sNOOOpy is very simple and potentially applicable to a wide variety of living cells and is expected to provide insights into NO 3 −/NO 2 − dynamics in various organisms, including plants and animals.”