S42: Regressive Methods for Generating Biosynthetic Pathways for Synthetic Compounds

Using a combination of structure-based enzyme redesign and directed evolution methodologies, along with new biosynthetic pathway construction paradigm, we have developed microbial based pathways capable of producing two synthetic nucleoside analogs, dideoxyinosine (Didanosine) and ribavirin monophosphate. In the first case, we apply a ‘bioretrosynthetic’ sequence for the assembly and evolution of didanosine biosynthesis. Three enzymes are recruited and two optimized to produce a prototype pathway capable of producing this valuable synthetic AIDS drug. In the second case, we describe a ‘survival of the least fit paradigm’ for the selection of improved biosynthetic variants for the production of the antiviral nucleoside analog ribavirin monophosphate and a subsequent pathway articulation in a covalently linked enzyme aggregate.