CAREER: Discovering and Engineering Protein-Based Sensors for Nitrate in Biology

With the support of the Chemistry of Life Processes Program in the Chemistry Division, Sheel C. Dodani from The University of Texas at Dallas will study the biochemistry of the nitrate oxyanion. It is widely recognized that nitrate is required for essential functions in bacteria and plants such as respiration, growth, and signaling. However, much remains unknown about the beneficial and detrimental effects of nitrate in humans. To fill this knowledge gap, the Dodani Lab will study and engineer protein sensors in an effort to develop nitrate-selective sensors. If successful, such proteins have the potential to detect nitrate in living cells, and, in the longer term, shed light on the biochemical roles of nitrate. These efforts will be coupled to an educational plan that seeks to illustrate the biochemical significance of anions such as nitrate through interactions with food-based proteins by developing a general chemistry laboratory course for undergraduate students entitled Hofmeister in the Kitchen. Nitrate is an essential inorganic ion for life. In bacteria and plants, nitrate is a well-studied nutrient and signaling ion; in humans, nitrate has been overshadowed by reactive nitrogen oxides. To dissect the contributions of nitrate in human biology, a fundamental understanding of its cellular uptake, regulation, and targets is needed. Optical imaging approaches with nitrate-selective fluorescent biosensors can accelerate the path to gain these insights in living cells. However, such technologies remain rare due to the inherent difficulty of aqueous anion recognition. To overcome this fundamental challenge, the Dodani research team will investigate proteins as biological supramolecular hosts for nitrate. Specifically, nitrate binding proteins are being identified through bioinformatics, and will be characterized with biophysical methods, and used to engineer fluorescent protein-based sensors for cellular applications. This interdisciplinary approach is expected to begin to unravel the sequence level molecular determinants that confer and tune biomolecular nitrate recognition. The goal is to develop and/or identify selective protein sensors for nitrate, a major challenge at the chemistry/biology interface. The larger molecular theme of this science is to illuminate the roles of nitrate in biology. The protein-based tools being developed in this project are expected to help address this basic question and as such have broad scientific impact at the chemistry-biology interface. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.