This application proposes to continue the investigation of some of the key enzymes in the shikimate-chorismate pathway. The long term objectives are to elucidate the mechanisms of these enzymes and to develop general strategies for the design of enzyme inhibitors. (1) Dehydroquinase. Substrate analogs capable of aromatization and irreversible covalent linkage to the Type I DHQases are proposed. (2) EPSP Synthase. The intermediate involved in the addition/elimination mechanism of this enzyme, along with its monofluoro analog, will be synthesized to complete a series of tetrahedral analogs. A project in structure-derived inhibitor design, based on the structures of the inhibitor-enzyme complexes, will be initiated. (3) Chorismate Synthase. Some of the remaining mechanistic issues for this enzyme will be resolved by synthesizing and evaluating halo- and cyclopropanated substrate analogs. (4) Chorismate Mutase. New inhibitors of this unique enzyme are proposed, based on the structural information now available on its complex with previous inhibitor; new designs include a ring-expanded analog, potential irreversible inhibitors, and alternative substrates that can differentiate the mechanisms by which the enzymatic and catalytic antibody reactions are accelerated. (5) Shikimate Analogs. A number of analogs of shikimate itself, as well as their 5-enol-pyruvyl-3-phospho-isosteres, will be synthesized and evaluated as alternative substrates for a number of enzymes in the pathway. These analogs include 4-epi-shikimate, 2-halo- shikimates, and 5-membered ring analogs. (6) Isochorismate, Anthranilate, and p-Aminobenzoate Synthases. The project in this area will be concluded through the synthesis of an alternative series of bisubstrate analogs as potential inhibitors of the latter enzyme.
