PyShell crucial for efficient CO2 fixation
In plants and algae, photosynthesis takes place in chloroplasts. Inside these chloroplasts, energy from sunlight is harvested by thylakoid membranes and then used to help the enzyme Rubisco fix CO2. However, algae have an advantage: they pack all their Rubisco into small compartments called pyrenoids, where CO2 can be captured more efficiently. “We have now discovered that diatom pyrenoids are encased in a lattice-like protein shell,” says Dr. Manon Demulder, author on both studies. “The PyShell not only gives the pyrenoid its shape, but it helps create a high CO2 concentration in this compartment. This enables Rubisco to efficiently fix CO2 from the ocean and convert it into nutrients.”
When the researchers removed the PyShell from the algae, their ability to fix CO2 was significantly impaired. Photosynthesis and cell growth were reduced. “This showed us how important the PyShell is for efficient carbon capture – a process that is crucial for ocean life and the global climate,” says Manon Demulder.
Bioengineering for CO2 reduction?
The discovery of the PyShell could also open promising avenues for biotechnological research aimed at combatting climate change – one of the most pressing challenges of our time. “First of all, we humans must reduce our CO2 emissions to slow the pace of climate change. This requires immediate action,” says Ben Engel.
“The CO2 that we emit now will remain in our atmosphere for thousands of years. We hope that discoveries such as the PyShell can help inspire new biotechnology applications that improve photosynthesis and capture more CO2 from the atmosphere. These are long-term goals, but given the irreversibility of CO2 emissions, it is important that we perform basic research now to create more opportunities for future carbon-capture innovations.”
Contact: Communications Biozentrum
Original Publications:
Ginga Shimakawa, Manon Demulder, Serena Flori, Akihiro Kawamoto, Yoshinori Tsuji, Hermanus Nawaly, Atsuko Tanaka, Rei Tohda, Tadayoshi Ota, Hiroaki Matsui, Natsumi Morishima, Ryosuke Okubo, Wojciech Wietrzynski, Lorenz Lamm, Ricardo D. Righetto, Clarisse Uwizeye, Benoit Gallet, Pierre-Henri Jouneau, Christoph Gerle, Genji Kurisu, Giovanni Finazzi, Benjamin D. Engel, Yusuke Matsuda: Diatom pyrenoids are encased in a protein shell that enables efficient CO2 fixation. Cell. Published online October 1, 2024. doi.org/10.1016/j.cell.2024.09.013
Onyou Nam, Sabina Musial, Manon Demulder, Caroline McKenzie, Adam Dowle, Matthew Dowson, James Barrett, James N. Blaza, Benjamin D. Engel, Luke C. M. Mackinder: A Protein Blueprint of the Diatom CO2-Fixing Organelle. Cell. Published online October 4, 2024. doi.org/10.1016/j.cell.2024.09.025