Functions and mechanisms of metalloenzymes in natural product and cofactor biosynthesis

The National Institute of General Medical Sciences awarded Duke University $737,152 on March 10, 2026, under the Biomedical Research and Research Training program (CFDA 93.859) to elucidate the mechanisms and functions of metalloenzymes in cofactor and natural product biosynthesis.

The research focuses on structural and mechanistic characterization of two enzyme families: radical S-adenosyl-L-methionine (RSAM) enzymes that catalyze oxygen-independent radical-mediated reactions, and non-heme iron-dependent oxygenases and oxidases. The work addresses key questions including substrate-triggered radical initiation mechanisms in RSAM enzymes and C-H or O-H activation mechanisms by mono- or dinuclear iron cofactors. Results will bridge knowledge gaps between bioorganic and bioinorganic chemistry and advance understanding across cofactor and natural product biosynthesis and metalloenzymology. The project consolidates two ongoing NIGMS R01 projects.

Duke University's Office of Research Administration, located in Durham, North Carolina, is the recipient. Performance occurs in Durham, NC 27710. The period of performance extends from the award date through December 31, 2030.

Abstract

Metalloenzymes frequently catalyze chemically challenging radical-mediated reactions necessary for the synthesis of the complex structures of natural products and cofactors. Their functional and mechanistic characterization has been a critical basis for the discovery and development of small molecule therapeutics, research probes, and biocatalysts. However, many metalloenzymes in natural product and cofactor biosynthetic pathways remain significantly under-explored because (1) characterization of metalloenzymes requires specialized expertise and techniques due to the unique reactivities and properties of their metallo- centers, (2) their substrates are frequently not readily available, and (3) their functions may not be apparent from their primary amino acid sequence or structural homologies. Consequently, many metalloenzymes remain under- or unexplored, leaving numerous mechanistic questions unanswered. The long-term goal of my group is to elucidate the mechanisms and functions of metalloenzymes in cofactor and natural product biosynthesis. This application combines two ongoing nigms R01 projects and focuses on O2-independent and dependent FE enzymes: radical s-adenosyl-l-methionine (rsam) enzymes and non-heme iron-dependent oxygenases/oxidases. The proposed structural and mechanistic characterizations will reveal novel catalytic functions and mechanisms of (metallo)enzymes and address key questions in each enzyme family, including the mechanism of substrate-triggered radical initiation by rsam enzymes and the mechanism of c-h or o-h activation by mono or dinuclear FE cofactors. The results of these studies will uniquely bridge the knowledge GAP between bioorganic and bioinorganic chemistry and broadly impact the fields of cofactor and natural product biosynthesis and metalloenzymology.