Dinuclear iron enzymes (DIs) utilize a carboxylate- and histidine-coordinated cofactor to affect synthetically challenging biochemical reactions. The recognized roles for DIs have recently expanded to include several important natural product biosynthetic pathways, including the generation of folate in pathogenic bacteria, the modulation of antibiotic potency via halogen installation, and the synthesis of essential secondary metabolites through carbon-carbon bond scission. To understand the molecular basis for how a very similar cofactor and structural core can perform such diverse functions, we propose to study three newly discovered DIs that contain nearly identical coordination motifs and overall structural scaffolds, but orchestrate chemistry in ways that fundamentally differ from both each other and from well-studied DIs that instead perform the oxygenation of substrates. The proposed work will utilize an array of spectroscopic, kinetic, and genetic tools to identify key sites of the protein, substrate, and cofactor that enable such disparate activities. An elucidation of the structural basis for DI functional reprogramming will provide a biochemical template for the synthesis of new pharmacophores and the molecular basis for pathways that are critical for microbial proliferation and pathogenicity.
Carboxylate-bridged dinuclear iron enzymes are responsible for synthesizing a diverse array of natural products. This program investigates the molecular basis for the varied biochemical roles of several newly discovered diiron enzymes that share similar structures but perform very different chemical reactions. An understanding for how these enzymes differentially activate dioxygen and metabolize substrates will illuminate the basis for the synthesis of pharmacophores and secondary metabolites that are critical for microbial pathogenicity and proliferation.
