Expanding the Metabolic Currencies of Life

There is an unmet need to obtain natural product-derived medicines in a scalable and reliable manner. Natural products are small molecules produced by biological systems, but often in low quantities. Synthetic biology promises to move the biosynthetic pathways of these medicinal small molecules from their native

producers into heterologous hosts such as bacteria and yeast or into a bioreactor, so that large-scale, low-cost, industrial processes can be developed to produce them. The long-term goal of my research program is to address the ultimate challenge in chemical biosynthesis, namely to precisely control the flow of electrons,

carbon, and energy. Over the past five years, we have made substantial strides toward this goal, by establishing unnatural electron currency which operates in parallel to Nature's universal cofactor. This design is inspired by Nature: Catabolism and anabolism, two opposing metabolic systems responsible for breaking

down and building up cell components, respectively, are insulated from each other because they each have a designated redox cofactor, NAD and NADP, respectively. We have demonstrated that our unnatural cofactor can indeed precisely channel reducing power only to the desired pharmaceutical producing reactions inside the

cells while silencing all side-reactions, effectively insulting the biosynthetic pathway from the host's complex native metabolism. Importantly, we have also developed universal, high-throughput, growth-based selection platforms to readily obtain enzymes that can use the unnatural cofactor. Through these efforts, general

enzyme design principles also start to emerge which paves the way for our proposed work in the next five year. Through the MIRA support, we will develop methods to drastically improve the efficiency of the unnatural cofactor technology; make it easy to adopt by bioengineering community; bring this technology to bear on

difficult high-reward biosynthesis challenges; broaden the category of unnatural metabolic currencies from electron- to carbon- and energy-carriers and distill translatable design principles; use this project as a vehicle to include and promote diverse STEM researchers at K-12, undergraduate, graduate, and post graduate

stages. The proposed work is transformative because it directly targets life's universal metabolic infrastructure and therefore can have extremely broad impacts in biomedicine and synthetic biology.