Enzyme engineering for biosynthetic cascades

Abstract Biosynthetic cascades represent a transformative technology that is revolutionizing the way chemists approach synthetic challenges and have set new standards for what constitutes green and sustainable chemistry. Early work in this field was focused on the production of natural products both in vivo or in vitro, and therefore relied upon the use of naturally occurring enzymes. While natural products continue to be a source of useful chemical matter, synthetic derivatives of natural products or wholly synthetic molecules are dominant drivers of pharmaceutical and fine-chemical demand. Consequently, natural enzymes are insufficient or ineffective as catalysts and often require extensive protein engineering—to alter a range of properties—before they can be useful. Here we review the extensive progress achieved in protein engineering as applied to syntheses containing multiple concurrent or sequential enzyme-catalyzed synthetic steps both in vivo and in vitro from 2018 to 2020.