PROJECT SUMMARY The Chemistry and Biology of Tetrapyrroles Gordon Research Conference (GRC) is the largest and broadest international meeting for sharing and discussing the latest research on tetrapyrroles, a diverse group of protein cofactors and metabolites which include heme, cobalamin (vitamin B12), chlorophyll, and bilins. Tetrapyrroles serve as important cofactors to control essential cellular processes important for normal homeostasis and development. In addition, tetrapyrroles also serve as a nutrient source and important signaling and regulatory molecules in normal and disease states with broad implication on human health. This meeting serves as the premier conference to present new unpublished tetrapyrrole related research findings; gather international scientists at a variety of levels including senior scientists with early stage investigators (ESI) and trainees in both formal and informal environments to create new connections and collaborations to advance the chemistry and biology of tetrapyrroles; and provide and foster an inclusive environment for the development of diverse scientists in an equitable and open setting. The 2022 GRC meeting will be held from July 17 - 22, 2022 at Salve Regina University in Newport, RI. The Chemistry & Biology of Tetrapyrroles GRC is one of a kind in terms of the international and diverse audience that it attracts. The broad diversity of topics include clinical, biological, and chemical aspects of tetrapyrroles. In addition, the range of organisms is equally as broad and spans from bacteria to humans. The 2022 GRC will integrate research from a variety of researchers at different levels in the following areas: new structural techniques to study tetrapyrroles; trafficking, signaling and regulation by heme; the many facets of bilins; tetrapyrroles in human health and disease; the biology of tetrapyrroles; the many faces of B12; the regulation and biosynthesis of chlorophyll pigments; and microbial tetrapyrrole metabolism. Given the critical roles that tetrapyrroles play in pathogenesis of infectious disease, host immunity, normal cellular development and metabolism, understanding the synthesis, regulation, degradation, and trafficking of tetrapyrroles is crucial for human health.