Because life at the molecular level is the chemistry of carbon containing compounds, reactions that make carbon-carbon bonds are particularly valuable. A challenge for making compounds from carbon is the formation of closely related versions or isomers as products from a single reaction. The most closely related isomers are called stereoisomers, otherwise identical compounds, but mirror images of each other. The proposal envisions harnessing the power of biological transformations for carbon-carbon bond formation that make single stereoisomers for the production of practical compounds like pharmaceuticals. The reactions would not only be exquisitely specific, but also environmentally friendly, or "green" by using only natural materials and gentle conditions. The research plan involves the re-engineering of proteins using recombinant DNA technology so that they specifically make high-value products. The projects that make up the plan will enable interdisciplinary training of graduate students, postdoctoral fellows and undergraduates in the fields of enzymology, molecular biology, protein engineering, and chemical synthesis.
With this award, the Chemistry of Life Processes Program in the Chemistry Division is funding Drs. Frank Jordan and Edgardo T. Farinas, of Rutgers University-Newark Campus and the New Jersey Institute of Technology, respectively, to undertake enzymatic synthesis of chiral alpha-hydroxy ketones for pharmaceuticals, and fine chemicals for synthesis of larger molecules. For the first time the 2-oxoglutarate dehydrogenase multienzyme complex (OGHDc), both human and E. coli, and 2-hydroxy-3-oxoadipate synthase from Mycobacterium tuberculosis (HOAS), will be engineered to create these compounds. The principal investigators have already demonstrated that the first OGDHc component (E1o) is an efficient biocatalyst using the physiological substrate. To enhance the power of this carboligation reaction, they will: (1) Engineer residues from the substrate binding site selected from X-ray structures of the E1os and HOAS to accept a variety of substrates for efficient enzymatic synthesis of alpha-hydroxy ketones, with high enantiomeric excess (ee) and yield; (2) Explore alterations in the chemical nature of donor 2-oxo acid and of acceptor aldehyde. (3) Advance the field of biocatalysis by engineering not only E1os but the second E2o core component of OGDHc to accept unnatural substrates leading to acyl-coenzyme A analogues participating in many metabolic pathways; (4) Explore the mechanism of intra-E2o component acyl transfer to coenzyme A.
