Saccharomyces cerevisiae as a platform for derivatization and bioproduction of bioactive natural product scaffolds

Monoterpene indole alkaloids (MIAs) are a diverse class of plant secondary metabolites with potent pharmaceutical properties. However, their complex structure precludes total synthesis on an industrial scale, meaning that despite their clinical usefulness they are sourced from native plants at great economic and environmental cost. This group has recently refactored key elements of the biosynthetic pathways in baker’s yeast Saccharomyces cerevisiae, establishing microbial synthesis as a novel supply chain for these important medicines. In addition to the production benefits, the advanced engineering toolbox associated with microorganisms also facilitates further manipulation of the pathway in a way that was not possible in plants. In this thesis, we report development of novel yeast strains and protocols optimized for the production of new-to-nature MIA derivatives, broadening the application of microbial synthesis from drug production to drug discovery. The scope and goals of the project are introduced in a published review that outlines specific opportunities for microbial synthesis for drug discovery. These opportunities are then followed up on in work that resulted in microbial semi-synthesis of more than 80 halogenated MIA derivatives and de novo synthesis of a chlorinated variant of alstonine. In the final chapter, focus switched from demonstrating the broad versatility of the platform to producing and testing a purified sample of 6-fluororauwolscine, a novel rauwolscine derivative.