Artificial condensates can boost metabolic engineering

Nicotiana benthamiana is widely used to reconstruct complex, multi-step metabolic pathways for research or industrial purposes. This is enabled by rapid and high-level protein expression after agroinfiltration. Within cells, as well as membrane-bound organelles, nonmembrane-bound biomolecular condensates can spontaneously form with high concentrations of specific proteins and biochemicals. Battle et al. used the disordered RGG domain from a C. elegans protein known to phase separate, and engineered a scaffold to create synthetic condensates in N. benthamiana. One half of a cognate pair of synthetic coiled-coil peptides (SYNZIP1) is bound to these RGG domains, and attaching the other to a protein of your choice recruits it to the condensate. These condensates were round, liquid-like, and showed molecular exchange between condensates, key characteristics of phase-separating systems. While in this condensate, proteins were shown to have increased stability, and their activity may also be boosted due to proximity to their substrates and protection from degradation. The usefulness of this system was demonstrated using the citramalate biosynthesis pathway, used in plastic manufacturing. By targeting citramalate synthase to condensates, the level of citramalate produced more than doubled. These advances could improve the use of N. benthamiana as factories for the production of economically and industrially important chemical compounds.  (Summary by Ciara O’Brien @ciara-obrien.bsky.social) Plant Biotechnol. J. 10.1111/pbi.70082