Pyrenoid functions revealed by proteomics in Chlamydomonas reinhardtii

• DOI: 10.1371/journal.pone.0185039
• Publication Date: 2018-02-26T13:28:24Z
• Authors: Yu Zhan; Christophe H. Mar...; Alexandre Maes; Adeline Mauries; Yi Sun; James S. Dhaliwal; James Uniacke; Simon Arragain; Heng Jiang; Nicholas D. Gold; Vincent J. J. Martin; Stéphane D. Lemaire; William Zerges
• Keywords: Pyrenoid; Chlamydomonas reinhardtii; Chlamydomonas; CLPB; Organelle

Organelles are intracellular compartments which themselves compartmentalized. Biogenic and metabolic processes localized to specialized domains or microcompartments enhance their efficiency suppress deleterious side reactions. An example of intra-organellar compartmentalization is the pyrenoid in chloroplasts algae hornworts. This microcompartment enhances photosynthetic CO2-fixing activity Calvin-Benson cycle enzyme Rubisco, suppresses an energetically wasteful oxygenase mitigates limiting CO2 availability aquatic environments. Hence, functionally analogous carboxysomes cyanobacteria. However, a comprehensive analysis functions based on its protein composition lacking. Here we report proteomic characterization green alga Chlamydomonas reinhardtii. Pyrenoid-enriched fractions were analyzed by quantitative mass spectrometry. Contaminant proteins identified parallel analyses pyrenoid-deficient mutants. proteome contains 190 proteins, many function that known proposed occur pyrenoids: e.g. carbon concentrating mechanism, starch metabolism RNA translation. Using radioisotope pulse labeling experiments, show pyrenoid-associated ribosomes could be engaged synthesis large subunit Rubisco. New supported tetrapyrrole chlorophyll synthesis, carotenoid amino acid metabolism. our results support long-standing hypothesis hub for The 81 unknown reveal candidates new participants these processes. Our provide biochemical evidence resource future research pyrenoids use agricultural plant productivity. Data available via ProteomeXchange with identifier PXD004509.