Elucidation of the biosynthetic pathway of reserpine

Reserpine is a landmark natural product that has profoundly influenced our understanding of neurotransmitter biology and cardiovascular medicine. Its complex structure, featuring a unique C3 β-configuration and five consecutive chiral centers, has inspired generations of synthetic chemists to develop innovative strategies for its construction. However, the biosynthetic logic underlying nature’s assembly of this intricate molecule has remained elusive. Here, we decipher the biosynthetic pathway of reserpine inRauvolfia verticillata, revealing that α-configured strictosidine serves as the biosynthetic precursor. The crucial C3 β-configuration is established through a two-step enzymatic epimerization, orchestrated by a flavin-dependent oxidase and a NADPH-dependent reductase. The consecutive chiral centers are constructed through coordinated action of distinct enzyme families. Through the identification of eight biosynthetic enzymes, including those catalyzing late-stage methoxylation, we successfully reconstituted the biosynthesis of rauvomitorine G, a key intermediate in reserpine formation. This work unveils nature’s elegant approach to stereoselective synthesis of complex alkaloids and provides valuable biocatalytic tools for molecular functionalization.