Imperial College London
Alternate

Professor Bill Rutherford FRS

Faculty of Natural Sciences, Department of Life Sciences

Chair in Biochemistry of Solar Energy
 
 
 
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Contact

 

+44 (0)20 7594 5329a.rutherford Website

 
 
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Location

 

702Sir Ernst Chain BuildingSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Rutherford:2016:10.1073/pnas.1608862113,
author = {Rutherford, AW and Fantuzzi, A and Brinkert, K and De, Causmaecker and Kreiger-Liszkay, A},
doi = {10.1073/pnas.1608862113},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
pages = {12144--12149},
title = {Bicarbonate-induced redox tuning in Photosystem II for regulation and protection},
url = {http://dx.doi.org/10.1073/pnas.1608862113},
volume = {113},
year = {2016}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - The midpoint potential (Em) of QA/Q−AQA/QA−•, the one-electron acceptor quinone of Photosystem II (PSII), provides the thermodynamic reference for calibrating PSII bioenergetics. Uncertainty exists in the literature, with two values differing by ∼80 mV. Here, we have resolved this discrepancy by using spectroelectrochemistry on plant PSII-enriched membranes. Removal of bicarbonate (HCO3−) shifts the Em from ∼−145 mV to −70 mV. The higher values reported earlier are attributed to the loss of HCO3− during the titrations (pH 6.5, stirred under argon gassing). These findings mean that HCO3− binds less strongly when QA−• is present. Light-induced QA−• formation triggered HCO3− loss as manifest by the slowed electron transfer and the upshift in the Em of QA. HCO3−-depleted PSII also showed diminished light-induced 1O2 formation. This finding is consistent with a model in which the increase in the Em of QA/Q−AQA/QA−• promotes safe, direct P+Q−AP+•QA−• charge recombination at the expense of the damaging back-reaction route that involves chlorophyll triplet-mediated 1O2 formation [Johnson GN, et al. (1995) Biochim Biophys Acta 1229:202–207]. These findings provide a redox tuning mechanism, in which the interdependence of the redox state of QA and the binding by HCO3− regulates and protects PSII. The potential for a sink (CO2) to source (PSII) feedback mechanism is discussed.
AU  - Rutherford,AW
AU  - Fantuzzi,A
AU  - Brinkert,K
AU  - De,Causmaecker
AU  - Kreiger-Liszkay,A
DO  - 10.1073/pnas.1608862113
EP  - 12149
PY  - 2016///
SN  - 1091-6490
SP  - 12144
TI  - Bicarbonate-induced redox tuning in Photosystem II for regulation and protection
T2  - Proceedings of the National Academy of Sciences of the United States of America
UR  - http://dx.doi.org/10.1073/pnas.1608862113
UR  - http://hdl.handle.net/10044/1/41802
VL  - 113
ER  -
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