Globins, the well characterized family of oxygen-binding proteins from animals and plants, were discovered also to be in bacteria by Warburg in the 1930s. Recent findings from the PI's lab now extend the distribution of these proteins to include the third domain of life, the Archaea. This project will focus on the function of two globin-like proteins, one from a bacterium and another from an archaeon. The work will analyze how these proteins sense and relay signals about oxygen levels in the environment in a manner such that cells can move towards oxygen concentrations ideal for their metabolism. The aim is to determine how the interaction of these proteins with oxygen transmits a signal to the intracellular machinery responsible for positioning the cell in environments with appropriate oxygen concentrations. Two hypotheses will be tested. One proposes that binding of oxygen to the protein induces conformational changes that are important in transmitting signals relating to oxygen concentrations in the environment. The second follows up the observation that, in the case of the archaeal globin, oxygen binding leads to the addition of methyl groups to the protein. A potential role for the methylated protein in adaptation to new ambient oxygen concentrations will be investigated. The project will adapt aspects of the research for use as a microbial signal transduction laboratory module for undergraduates: "Globin-Coupled Sensors as probes for understanding relationships between structure, function, and evolution for oxygen-sensing in Bacteria and Archaea." Overall, this project pulls together resources and methods from bioinformatics, genetics, biophysics, biochemistry, and physiology to answer key questions about signal transduction of the globin-coupled sensors. An improved understanding of the globin-coupled sensors promises advances not only in controlling the interactions of oxygen with sensing and signaling domains, but also may serve as models for biological functions, including protection from nitrosative and oxidative stress.
