Redox-coupled proton pumping drives carbon concentration in the photosynthetic complex I

Photosynthetic organisms capture light energy to drive their energy metabolism, and employ the chemical reducing power to convert carbon dioxide (CO 2 ) into organic molecules. Photorespiration, however, significantly reduces the photosynthetic yields. To survive under low CO 2 concentrations, cyano...

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Veröffentlicht in:Nature communications 2020-01, Vol.11 (1), p.494-494, Article 494
Hauptverfasser: Schuller, Jan M., Saura, Patricia, Thiemann, Jacqueline, Schuller, Sandra K., Gamiz-Hernandez, Ana P., Kurisu, Genji, Nowaczyk, Marc M., Kaila, Ville R. I.
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Sprache:eng
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Zusammenfassung:Photosynthetic organisms capture light energy to drive their energy metabolism, and employ the chemical reducing power to convert carbon dioxide (CO 2 ) into organic molecules. Photorespiration, however, significantly reduces the photosynthetic yields. To survive under low CO 2 concentrations, cyanobacteria evolved unique carbon-concentration mechanisms that enhance the efficiency of photosynthetic CO 2 fixation, for which the molecular principles have remained unknown. We show here how modular adaptations enabled the cyanobacterial photosynthetic complex I to concentrate CO 2 using a redox-driven proton-pumping machinery. Our cryo-electron microscopy structure at 3.2 Å resolution shows a catalytic carbonic anhydrase module that harbours a Zn 2+ active site, with connectivity to proton-pumping subunits that are activated by electron transfer from photosystem I. Our findings illustrate molecular principles in the photosynthetic complex I machinery that enabled cyanobacteria to survive in drastically changing CO 2 conditions. Cyanobacteria evolved carbon-concentration mechanisms to enhance the efficiency of photosynthetic CO 2 fixation, but the molecular principles have remained unknown. Here authors use cryo-EM to reveal how modular adaptations enabled the photosynthetic complex I from the cyanobacterium Thermosynechococcus elongatus to concentrate CO 2 .
ISSN:2041-1723
2041-1723
DOI:10.1038/s41467-020-14347-4