Our laboratory studies the chemistry of biology and energy. We advance new concepts in imaging, proteomics, drug discovery, and catalysis by drawing from core disciplines of inorganic, organic, and biological chemistry. For example, we have developed activity-based sensing as a general platform to identify transition metals, reactive oxygen species, and one-carbon units as new classes of single-atom signals for allosteric regulation of protein function. These chemical tools also reveal unique metal and redox disease vulnerabilities as targets for innovative drug discovery efforts to treat neurodegeneration, cancer, and metabolic disorders. Our work in artificial photosynthesis addresses global challenges in climate change. We use design concepts from biology to develop molecular electrocatalysts for carbon dioxide capture and conversion and nitrogen/phosphorus cycling. Representative project areas are summarized below.