RT Journal Article
SR Electronic
T1 A Protein Blueprint of the Diatom CO<sub>2</sub>-Fixing Organelle
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 2023.10.26.564148
DO 10.1101/2023.10.26.564148
A1 Nam, Onyou
A1 Musial, Sabina
A1 Demulder, Manon
A1 McKenzie, Caroline
A1 Dowle, Adam
A1 Dowson, Matthew
A1 Barrett, James
A1 Blaza, James N.
A1 Engel, Benjamin D.
A1 Mackinder, Luke C. M.
YR 2024
UL http://biorxiv.org/content/early/2024/09/24/2023.10.26.564148.abstract
AB Diatoms are central to the global carbon cycle. At the heart of diatom carbon fixation is an overlooked organelle called the pyrenoid, where concentrated CO2 is delivered to densely packed Rubisco. Diatom pyrenoids fix approximately one-fifth of global CO2, but virtually nothing is known about this organelle in diatoms. Using large-scale fluorescence protein tagging and affinity purification-mass spectrometry, we generate a high-confidence spatially-defined protein-protein interaction network for the diatom pyrenoid. Within our pyrenoid interaction network are 10 proteins with no known function. We show that six of these form a static shell encapsulating the Rubisco matrix of the pyrenoid, with the shell critical for pyrenoid structural integrity, shape, and function. Although not conserved at a sequence level, the diatom pyrenoid shares some architectural similarities to prokaryotic carboxysomes. Collectively, our 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.Competing Interest StatementThe authors have declared no competing interest.