De Novo Production of the Plant-derived Tropine and Pseudotropine in Yeast.

Tropine and pseudotropine with opposite stereospecific configurations as platform compounds are central building blocks in both biosynthesis and chemical synthesis of pharmacologically important tropane and nortropane alkaloids. The supply of plant-derived tropine and pseudotropine still heavily depends on either plant extraction or chemical synthesis. The advances in synthetic biology prompt the microbial synthesis of various valuable chemicals. With the biosynthetic pathway elucidation of tropine and pseudotropine in several Solanaceae plants, the key genes were sequentially identified. Here, the enzymes responsible for converting N-methylpyrrolinium into tropine and pseudotropine from Anisodus acutangulus were characterized. Reconstruction of the 6-step biosynthetic pathways into Saccharomyces cerevisiae provides cell chassis producing tropine and pseudotropine with 0.13 and 0.08 mg/L titers from simple feedstocks in shake flask, respectively. The strains described not only offer alternative sources of these central intermediates and their derived alkaloids but also provide platforms for pathway enzyme discovery.