Liquid-liquid phase separation-driven enzyme catalysis for efficient biosynthesis of isoprenoid natural products.

Liquid-liquid phase separation (LLPS)-mediated formation of membraneless, biomolecule-rich organelles formed via LLPS is critical to numerous biological processes, but how this spatiotemporal control enables efficient catalysis by biosynthetic enzymes to produce natural products (NPs) remains poorly understood. Here, we demonstrate that two C7/C6-dimethylallyl tryptophan synthases (DMATSs), IsaA/InaA and a tryptophanase IsaB, from Streptomyces possess intrinsically disordered regions (IDRs) to undergo LLPS. IDRs from IsaA/InaA are required for enzyme activity, while the IDR from IsaB is not, but it mediates enzyme interaction and preferentially undergoes inter-IDR condensation with IsaA, leading to stronger LLPS and efficient catalysis of cascade reactions to produce isoprenyl alkaloids. These properties were leveraged for enzyme engineering with the IsaA IDR to enhance the catalytic efficiency of taxadiene synthase, and with interactive IDRs from IsaA/IsaB to improve the production of taxadiene and farnesyl-pyrophosphate. Our work proposes LLPS-mediated catalysis regulation and demonstrates new orthogonal toolkits for efficient biosynthesis of isoprenoid NPs.