UC Davis

Enzymes play a monumental role in medicine, materials science, food science, agriculturaltechnology, and energy. These natural catalysts allow us to explore chemical reactions that often exceed the capabilities of traditional synthetic chemistry, with the advantage of usually operating under mild conditions and temperatures. Even so, there valuable reactions for which either there exists no natural enzyme or we haven’t discovered it yet. To address this problem, we have taken notes from nature and used its powerful tool of evolution to alter the functionality of enzymes to impose the activity we want. Now, with genome sequencing being practically free, and the sequences of millions of proteins available at our fingertips, the possibilities for engineering any reaction we want in an enzyme are limited only by our imaginations. These tools combined with the unprecedented power of computers to explore sequence space, and to detect patterns humans can’t even see present the opportunity to design novel enzymes and rapidly re-engineer enzymes to service nearly any industry. For my thesis, I used the power of enzyme engineering to explore the production of flavonoids, a secondary metabolite found in plants, and specifically anthocyanins, a colorful class of compounds sought after as a natural source of food coloring by food manufacturers aiming for cleaner labels. Flavonoids are a massive class of compounds that are highly similar, often differing in a single sugar or glucose group. These similarities make them an ideal target to exploit and engineer to regio- and stereo- specificity of enzymes to biosynthesize these products for use in medicine and material sciences. I explore using enzymes to make them in several ways. My first chapter looks at building them from the ground up through the investigation of glycosyltransferases, a massive and extremely valuable class of enzymes. I then look at isolating single anthocyanins from complex mixtures via selective degradation with engineered enzymes, a process that could be easy to implement and valuable for manufacturing these compounds at an industrial scale.