The state of oligomerization of Rubisco controls the rate of synthesis of the Rubisco large subunit in <i>Chlamydomonas reinhardtii</i>

ABSTRACT Ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) is present in all photosynthetic organisms and a key enzyme for photosynthesis-driven life on Earth. Its most prominent form hetero-oligomer which small subunits (SSU) stabilize the core of built from large (LSU), yielding, after chaperone-assisted multistep assembly process, an LSU8SSU8 hexadecameric holoenzyme. Here we use Chlamydomonas reinhardtii combination site-directed mutants to dissect biogenesis pathway Rubisco vivo. We identify intermediates, two LSU are associated with RAF1 chaperone. Using genetic biochemical approaches further unravel major regulation process during biogenesis, translation controlled by its ability assemble SSU, via mechanism control epistasy synthesis (CES). Altogether this leads us propose model whereby last intermediate, LSU8-RAF1 complex, provides platform SSU binding enzyme, when not available, converts regulatory that exerts negative feedback initiation translation.