Assembly of the algal CO₂-fixing organelle, the pyrenoid, is guided by a Rubisco-binding motif.

ABSTRACT: Approximately one-third of the Earth's photosynthetic CO₂ assimilation occurs in a pyrenoid, an organelle containing the CO₂-fixing enzyme Rubisco. How constituent proteins are recruited to the pyrenoid and how the organelle's subcompartments-membrane tubules, a surrounding phase-separated Rubisco matrix, and a peripheral starch sheath-are held together is unknown. Using the model alga Chlamydomonas reinhardtii, we found that pyrenoid proteins share a sequence motif. We show that the motif is necessary and sufficient to target proteins to the pyrenoid and that the motif binds to Rubisco, suggesting a mechanism for targeting. The presence of the Rubisco-binding motif on proteins that localize to the tubules and on proteins that localize to the matrix-starch shea

SUBMITTER: Meyer MT 

PROVIDER: S-EPMC7673724 | biostudies-literature | 2020 Nov

REPOSITORIES: biostudies-literature