biostudies-literatureAtkinson NLeverhulme TrustRCUK | Biotechnology and Biological Sciences Research CouncilWellcome TrustBiotechnology and Biological Sciences Research Council6303https://www.ebi.ac.uk/biostudies/studies/S-EPMC7726157biostudies-literatureUnknown11(1)Photosynthetic CO₂ fixation in plants is limited by the inefficiency of the CO₂-assimilating enzyme Rubisco. In most eukaryotic algae, Rubisco aggregates within a microcompartment known as the pyrenoid, in association with a CO₂-concentrating mechanism that improves photosynthetic operating efficiency under conditions of low inorganic carbon. Recent work has shown that the pyrenoid matrix is a phase-separated, liquid-like condensate. In the alga Chlamydomonas reinhardtii, condensation is mediated by two components: Rubisco and the linker protein EPYC1 (Essential Pyrenoid Component 1). Here, we show that expression of mature EPYC1 and a plant-algal hybrid Rubisco leads to spontaneous condensation of Rubisco into a single phase-separated compartment in ArabidNature communicationsCondensation of Rubisco into a proto-pyrenoid in higher plant chloroplasts.PMC7726157RPG-2017-402BB/S015337/1WT104915MABB/S015531/1Atkinson NMcCormick AJChan KXMao YfalseCondensation of Rubisco into a proto-pyrenoid in higher plant chloroplasts.Photosynthetic CO₂ fixation in plants is limited by the inefficiency of the CO₂-assimilating enzyme Rubisco. In most eukaryotic algae, Rubisco aggregates within a microcompartment known as the pyrenoid, in association with a CO₂-concentrating mechanism that improves photosynthetic operating efficiency under conditions of low inorganic carbon. Recent work has shown that the pyrenoid matrix is a phase-separated, liquid-like condensate. In the alga Chlamydomonas reinhardtii, condensation is mediated by two components: Rubisco and the linker protein EPYC1 (Essential Pyrenoid Component 1). Here, we show that expression of mature EPYC1 and a plant-algal hybrid Rubisco leads to spontaneous condensation of Rubisco into a single phase-separated compartment in Arabid2020-01-01T00:00:00Z2020 Dec2025-04-22T13:40:47.78Z2025-04-06T00:42:05.882ZS-EPMC77261573329892310.1038/s41467-020-20132-0