Mobile hydrogen carbonate acts as proton acceptor in photosynthetic water oxidation
2014 (English)In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 11, no 17, 6299-6304 p.Article in journal (Refereed) Published
Cyanobacteria, algae and plants oxidize water to the O2 we breathe, and consume CO2 during the synthesis of biomass. Although these vital processes are functionally and structurally well separated in photosynthetic organisms, there is a long-debated role for CO2/HCO3− in water oxidation. Using membrane-inlet mass spectrometry we demonstrate that HCO3− acts as a mobile proton acceptor that helps to transport the protons produced inside of photosystem II by water-oxidation out into the chloroplast's lumen, resulting in a light-driven production of O2 and CO2. Depletion of HCO3− from the media leads, in the absence of added buffers, to a reversible down-regulation of O2 production by about 20%. These findings add a previously unidentified component to the regulatory network of oxygenic photosynthesis, and conclude the more than 50-y-long quest for the function of CO2/ HCO3− in photosynthetic water oxidation.
Place, publisher, year, edition, pages
National Academy of Sciences , 2014. Vol. 11, no 17, 6299-6304 p.
carbon dioxide, bicarbonate, proton release, oxygen evolution, water splitting
Biophysics Physical Chemistry
IdentifiersURN: urn:nbn:se:umu:diva-86300DOI: 10.1073/pnas.1323277111ISI: 000335199000053OAI: oai:DiVA.org:umu-86300DiVA: diva2:698445
Included in thesis in manuscript form.2014-02-212014-02-212015-04-29Bibliographically approved