New Enzymes by Evolution: Expanding Nature’s Catalytic Repertoire

Synthetic biology for fuels and chemicals has depended on reassembling existing enzymes into new biosynthetic pathways.  Unfortunately, many desired transformations fall outside the reach of known enzyme-catalyzed transformations or can be made more efficiently using synthetic chemistry.  Thus, a future where metabolic engineering might produce nearly all of the organic molecules upon which society depends is still a ways off. Not satisfied with nature’s vast catalytic repertoire, we are want to be able to create new enzymes to add to the toolkit of genetically encoded chemistry. My group uses the one proven algorithm for biological design—evolution—to optimize existing catalysts and create whole new ones.  A powerful approach to engineering useful biological molecules, directed evolution both circumvents and underscores our profound ignorance of how sequence encodes catalytic function. I will describe various ways we have used evolution (contaminated with a little chemical intuition and design) to generate new catalysts starting from one of nature’s most impressive, the cytochrome P450 monooxygenase.  I will share several examples of engineered versions that catalyze important synthetic reactions not known in nature.