Engineering Sensors to Facilitate Multiplex Tuning of Biosynthetic Pathways

Metabolic pathways comprise several enzymes that progressively modify precursor molecules, resulting in a final product.  Varying the expression level of each component enzyme results in tradeoffs of metabolic load, enzymatic flux, and buildup of intermediates.  Therefore, in order to maximize the yield of a pathway, the optimal level of each enzyme must be determined.  In this work we present a novel method for rapid exploration of such an expression landscape.  Each component gene is placed under the control of a different, orthogonal small-molecule inducible system.  Adjusting the concentration of each inducer alters the expression of each gene, and the entire expression landscape can be probed using a single genetic construct.  In order to facilitate this approach, we continue to expand the number of inducible systems with the orthogonality and dynamic range necessary for such a system to function.