In-cell structure and variability of pyrenoid Rubisco.

ABSTRACT: Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) is central to global CO₂ fixation. In eukaryotic algae, its catalytic efficiency is enhanced through the pyrenoid - a protein-dense organelle within the chloroplast that concentrates CO₂. Although Rubisco structure has been extensively studied in vitro, its native structure, dynamics and interactions within the pyrenoid remain elusive. Here, we present the native Rubisco structure inside the green alga Chlamydomonas reinhardtii determined by cryo-electron tomography and subtomogram averaging of cryo-focused ion beam milled cells. Multiple structural subsets of Rubisco are identified, stochastically distributed throughout the pyrenoid. While Rubisco adopts an active conformation in the best-resolved map, compari

SUBMITTER: Elad N 

PROVIDER: S-EPMC12368222 | biostudies-literature | 2025 Aug

REPOSITORIES: biostudies-literature