Nam et al.(2024): A protein blueprint of the diatom CO2-fixing organelle
Onyou Nam, Sabina Musiał, Manon Demulder, Caroline McKenzie, Adam Dowle, Matthew Dowson, James Barrett, James N. Blaza, Benjamin D. Engel, Luke C.M. Mackinder IN: Cell, https://doi.org/10.1016/j.cell.2024.09.025
Using fluorescence protein tagging and affinity purification-mass spectrometry, the authors generate a high-confidence spatially defined protein-protein interaction network for the diatom pyrenoid. Within the pyrenoid interaction network are 10 proteins with previously unknown functions. They show that six of these form a shell that encapsulates the Rubisco matrix and is critical for pyrenoid structural integrity, shape, and function. Although not conserved at a sequence or structural level, the diatom pyrenoid shares some architectural similarities to prokaryotic carboxysomes. Collectively, the results support the convergent evolution of pyrenoids across the two main plastid lineages and uncover a major structural and functional component of global CO2 fixation.