The phase separation underlying the pyrenoid-based microalgal Rubisco supercharger.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 30498228.
- Also identified by DOI 10.1038/s41467-018-07624-w and PMC identifier 6265248.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
The slow and promiscuous properties of the CO<sub>2</sub>-fixing enzyme Rubisco constrain photosynthetic efficiency and have prompted the evolution of powerful CO<sub>2</sub> concentrating mechanisms (CCMs). In eukaryotic microalgae a key strategy involves sequestration of the enzyme in the pyrenoid, a liquid non-membranous compartment of the chloroplast stroma. Here we show using pure components that two proteins, Rubisco and the linker protein Essential Pyrenoid Component 1 (EPYC1), are both necessary and sufficient to phase separate and form liquid droplets. The phase-separated Rubisco is functional. Droplet composition is dynamic and components rapidly exchange with the bulk solution. Heterologous and chimeric Rubiscos exhibit variability in their tendency to demix with EPYC1. The ability to dissect aspects of pyrenoid biochemistry in vitro will permit us to inform and guide synthetic biology ambitions aiming to engineer microalgal CCMs into crop plants.
Medical subject headings
- Microalgae
- Ribulose-Bisphosphate Carboxylase