Deactivation of Protein Function and Mapping of Protein-Protein Interactions via Light-Induced Localized Oxidation

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With this award, the Chemistry of Life Processes Program in the Division of Chemistry is funding Professor Alexander Deiters at the University of Pittsburgh to develop new approaches to deactivate proteins and identify protein-protein interactions. Proteins, which are typically made up of naturally occurring amino acid units, play a wide range of roles in biological chemistry, including making chemical reactions faster and interacting with other proteins to start chemical and biological events. To understand the specific details of proteins involved in these events, Professor Deiters' team is developing new light-driven chemical reactions that change the atoms of only the key amino acid sites involved, which allows identification of the function of the protein or proteins crucial to the success of the chemical and biological events. The key amino acid sites are revealed by effectively weighing proteins after they have been marked with chemical reactions specific to the new atoms in the amino acids. Due to Professor Deiters' student recruiting strategies and the required combination of molecule making and protein chemistry, and cell biology, this project provides a unique training environment for the next generation of scientists at the interface of chemistry and biology, with them being highly diverse (greater than 60% from under-represented groups). Furthermore, to foster public understanding and interest in the research and training activities focused on light in biological processes, Professor Deiters and his team routinely offer outreach activities at local science museums. The hands-on outreach activities include the design of experiments that excite children at an early age about science, while showing them the involvement of chemistry in a range of everyday processes, such as reactions that make fireflies glow or sunscreens protect people from the sun's harmful rays. The site-specific introduction of photosensitive chromophores into target proteins enables spatial and temporal generation of singlet oxygen capable of reliably modifying protein structure and function with high precision. The approach is based on unnatural amino acid mutagenesis, followed by chromophore bioconjugation, thereby providing fully programmable control over the placement of singlet oxygen-generating chromophores. This affords exquisite control over the proximity of reactive oxygen species produced within protein surface landscapes and active sites. In addition to the light-triggered deactivation of protein function, the targeted protein oxidation enabled by this technology also allows for precise proximity-based labeling and pull-down, leading to the identification and mapping of protein-protein interactions.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.