Radical Mechanisms for Antibiotic and Herbicide Biosynthesis
EMSL Project ID
31191
Abstract
Antibiotic resistance is a major public health issue; hospital-acquired infections are now the fourth-leading cause of death in the United States. To address this problem, new antibiotics for clinical use are needed, and industrial processes for designing and synthesizing these drugs must be performed more efficiently at lower cost. The goal of our research is to elucidate enzyme mechanisms in antibiotic biosynthesis so that they can be engineered to generate novel compounds. We are particularly interested in methyltransferases from the radical SAM (S-adenosyl-L-methionine) protein superfamily. To date, none of the methyltransferases in this smaller group of radical SAM proteins has been characterized. In general, radical SAM enzymes catalyze difficult chemical reactions through the use of a 5-deoxyadenosyl radical. The deoxyadenosyl radical is generated upon homolytic cleavage of SAM, an equilibrium process that occurs when a reduced iron-sulfur cluster ([4Fe-4S]+1) in the protein provides SAM with an electron. We are investigating four related radical SAM methyltransferases.We hypothesize that all four proteins are radical SAM enzymes that also require a cobalamin (vitamin B12) for their methylation activity. We are interested in characterizing the iron-sulfur clusters of these proteins and identifying cobalamin intermediates/products or radical intermediates in order to establish the mechanism of these enzymes. These experiments are ideally performed using electron paramagnetic resonance (EPR) spectroscopy, so we are hopeful that we can collaborate with the NMR and EPR facility at EMSL on this research.
Project Details
Project type
Exploratory Research
Start Date
2009-01-29
End Date
2010-01-31
Status
Closed
Released Data Link
Team
Principal Investigator