CALVINASSEMBLY

Photosynthetic carbon fixation is catalyzed by the Calvin-Benson-Bassham cycle enzymes, soluble proteins conserved in all chloroplasts and forming high molecular masses species. We propose to apply an ensemble of experimental and numerical techniques to study the effect of different types of post-translational chemical modifications on the conformation of these proteins.Conditionally disordered peptide motifs would form interfaces with interaction partners that we will probe in vitro. We further propose that unknown assembly chaperones or scaffolding factors stabilize these large multi-molecular structures. Proteomic identification of the modifications and partners present during assembly in chromatographed cell extracts will then allow us to reconstruct these structures from isolated proteins for the determination of the high-resolution structure of complexes. We will then establish the structure-function relationships between protein-protein interactions and their allosteric effects on enzymatic activities. CALVINASSEMBLY aims at combining the analysis of posttranslational modifications, protein dynamics, and multi-protein complex formation in a more global model of the regulation of photosynthesis.