The evolution of shikimate associated metabolic enzymes

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In our study, we plan to use structural biology, biochemistry and molecular biology to understand how enzymes of the shikimate pathway have evolved their respective function. Based on this approach, we will functionally annotate classes of proteins whose biological function has not been previously determined. We will target plant and microbial enzymes that stem from the shikimate pathway. There are three main objectives in this proposal: 1) Investigate the evolution of function of SKL1 in chloroplast development. The shikimate pathway plays a central role for the biosynthesis of aromatic compounds in plants and microorganisms. The pathway leads to growth hormones, aromatic amino acids, flavonoids, lignin and other central metabolites in plants. As a result, this pathway is targeted for the development of inhibitors that could function as herbicide or antimicrobial agents. SKL1 is conserved across plant species analyzed, thus the functional annotation of this protein will provide opportunities to engineer crop plants to enhance their photosynthetic efficiency and thus increase their biomass. Inactivating SKL1 directly affects plant growth, therefore an SKL1 inhibitor could function as an effective herbicide. 2) Investigate the biosynthesis and role of Chlorogenic Acids (CGAs) in protecting plants against pathogens. Recently, we functionally annotated proteins involved in CGAs biosynthesis in plants. Although, it was known that plants produce chlorogenic acids, the early steps of the metabolic pathway had not been worked out. CGAs play an important role in our diet, they are powerful antioxidant and are associated with numerous health benefits including aging and protection against cardiovascular diseases. CGAs have powerful antifungal and antifeeding properties, therefore our ability to modulate the accumulation of CGAs at different developmental stages of fruit ripening is economically important. Our studies on CGA biosynthesis in plants will provide opportunities for crop protection. 3) Investigate the role of PCA in facilitating Listeria spp. interaction within the microbiome. We have elucidated the metabolic pathway for the utilization of quinate and shikimate for the production of protocatechuate; it is hypothesized that this compound is used by Listeria species to facilitate their interaction with other organisms in the environment. Decaying green vegetables have high quinate and shikimate content which is implicated in contributing to the growth of Listeria species. We therefore plan to develop strategies to disrupt Listeria interaction with other microorganisms and thus inhibit its ability to contaminate our food sources. The results from these studies will provide a better understanding of this interaction and opportunities to prevent Listeria contamination of food supply.