Carbon dioxide binding proteins that enhance yield in high value crops

CO2 is one of the most important gases on Earth. CO2 is essential to plants with regulatory functions in processes as diverse as photosynthesis, water utilisation, acidbase homeostasis, and immunity. Understanding the molecular basis by which CO2 influences protein function in plants is therefore crucial to the strategically important research area of plant responses to environmental change.
The global biome faces long term increases in atmospheric CO2. This is predicted to have a significant physiological impact on crops. For example, decreased water uptake at elevated CO2 levels is likely to have detrimental effects on the hydrological cycle. Furthermore, elevated CO2 is likely to decrease the nutritional content of strategically vital crops. Knowledge of the interactions between CO2 and proteins is therefore vital to understanding the challenges that face the 21st century food supply. Identification of protein targets for CO2 can be integrated with efforts to develop crops that can benefit from elevated CO2. Further, an understanding of how CO2 regulates protein function is essential for the development of protein based carbon capture, sequestration, and utilization systems. Unfortunately, the identities of plant proteins with which CO2 directly interacts are almost entirely unknown.
CO2 can form carbamates on the neutral N terminal amino and lysine amino-groups that regulate the activities of ribulose 1,5-bisphosphate carboxylase/oxygenase and haemoglobin, however, very few other protein carbamates are known. Tools for the systematic identification of protein carbamylation sites have not been developed owing to the ready reversibility of carbamate formation, and thus carbamylation is typically overlooked as a candidate for protein post-translational modification. We have developed methods to identify protein carbamates using chemical genetics to covalently trap CO2 on proteins for proteomic analysis. Our method demonstrates that carbamylation is widespread in biology. Protein-CO2 interactions therefore represents an exciting new and largely overlooked area of biochemistry that waits investigation.
This project will investigate protein-CO2 and the impact on plant physiological characteristics including yield. The student will use a combination of chemical genetics and mass spectrometry to identify new CO2-binding proteins. The impact of CO2-binding on protein function will be investigated through molecular biology and biochemistry. The influence of CO2-binding on protein function will be investigated through a combination of plant physiology, genetics and biochemistry. The project will therefore offer a truly multi-disciplinary training opportunity.
At the close of this project the student will have established carbamylation as a key mechanism for post translational modification mediating detection of CO2 in plants. This will expand our fundamental understanding of protein regulation. Further, on completion of the project, the student will have established the exciting and novel notion of a CO2-interacting proteome (the carbamylome).