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Quantification of bound bicarbonate in photosystem II
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Tikhonov, K. (author)
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- Shevela, Dmitry (author)
- Umeå universitet,Kemiska institutionen
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Klimov, V. V. (author)
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- Messinger, Johannes (author)
- Umeå universitet,Kemiska institutionen,Department of Chemistry, Molecular Biomimetics, Ångström Laboratory, Uppsala University, Uppsala, Sweden
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(creator_code:org_t)
- Institute of Experimental Botany, 2018
- English.
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In: Photosynthetica (Praha). - : Institute of Experimental Botany. - 0300-3604 .- 1573-9058. ; 56:1, s. 210-216
- Related links:
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https://urn.kb.se/re...
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https://doi.org/10.1...
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Abstract
Subject headings
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- In this study, we presented a new approach for quantification of bicarbonate (HCO3-) molecules bound to PSII. Our method, which is based on a combination of membrane-inlet mass spectrometry (MIMS) and O-18-labelling, excludes the possibility of "non-accounted" HCO3- by avoiding (1) the employment of formate for removal of HCO3- from PSII, and (2) the extremely low concentrations of HCO3-/CO2 during online MIMS measurements. By equilibration of PSII sample to ambient CO2 concentration of dissolved CO2/HCO3-, the method ensures that all physiological binding sites are saturated before analysis. With this approach, we determined that in spinach PSII membrane fragments 1.1 +/- 0.1 HCO3- are bound per PSII reaction center, while none was bound to isolated PsbO protein. Our present results confirmed that PSII binds one HCO3- molecule as ligand to the non-heme iron of PSII, while unbound HCO3- optimizes the water-splitting reactions by acting as a mobile proton shuttle.
Subject headings
- NATURVETENSKAP -- Biologi -- Biofysik (hsv//swe)
- NATURAL SCIENCES -- Biological Sciences -- Biophysics (hsv//eng)
Keyword
- hydrogen carbonate
- inorganic carbon
- mass spectrometry
- Mn-stabilizing protein
- non-heme iron
- ygen-evolving complex
Publication and Content Type
- ref (subject category)
- art (subject category)
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