CAREER: Characterization and Evolution of N-hydroxylase Biocatalysts: Solutions to Catalysis and Remediating Metal Pollution

Most bacteria create small molecules that bind to iron atoms. These molecules are called siderophores. Many siderophores can also bind toxic heavy metals. This project will search for siderophores with novel heavy metal binding activities in a polluted copper mine site in Vermont. Once found, the enzymes responsible for producing these metal-binding molecules will be identified and engineered for enhanced capabilities. The project will engage undergraduate women, including women of color, in research. There will also be community outreach in the form of annual workshops on climate justice involving the Urban League of Springfield’s Youth STEM enrichment program in Springfield, MA. Conserved sequence motifs identified in genes for novel siderophores isolated from a metal-polluted environment will be identified and characterized. Since alkyl diamine N-hydroxylase monooxygenases (NMOs) are involved in siderophore biosynthesis, the novel siderophores will likely be the product of unique NMOs. It is expected that NMOs involved in novel siderophore biosynthesis have broader substrate specificity, making them a target for identifying and developing new industrial biocatalysts. For example, hydroxylamines, valuable building blocks in the chemical and pharmaceutical industries, are enzymatically made in a single step from primary amines in the biosynthesis of hydroxamate siderophores. This project will characterize the selectivity of newly-identified NMOs and evolve these enzymes, increasing their yield and product diversity. 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.