My laboratory has been active in studying the regulation and enzymology of enzymes involved in the metabolism of bile acids and steroids by human intestinal bacteria. This work has included the elucidation of pathways involved in the metabolism of these compounds by bacteria and by liver enzymes. This interest has led to an ongoing collaboration with the laboratory of Dr. Everett C. Pesci, in which the focus of my laboratory is to elucidate the pathway of biosynthesis of the Pseudomonas Quinolone Signal (PQS). This signal molecule, 2-heptyl-3-hydroxy-4-quinolone, is produced by Pseudomonas aeruginosa and plays a central role in the regulation of numerous virulence factors in this organism which enable it to cause infections in plants, insects, and animals. Our work currently is focused on the pqsABCDE operon, specifically, the pqsA gene product, which we have determined to be an anthranilic acid – coenzyme A ligase. We are currently studying the kinetic and structural properties of this enzyme to identify potential inhibitors of the reaction and also to facilitate studies on the other gene products of the pqsABCDE operon. Our long term goal is to identify PQS-biosynthetic steps that can be targeted for disruption by specific antimicrobial compounds.