Abstract
The membrane-protein complex photosystem II (PSII) catalyzes photosynthetic water oxidation. Proton transfer plays an integral role in the catalytic cycle of water oxidation by maintaining charge balance to regulate and ensure the efficiency of the process. The hydrogen-bonded amino-acid residues that surround the oxygen-evolving complex (OEC) provide an efficient pathway for proton removal. Hence, it is crucial to identify these pathways to provide deeper insights into the proton-transfer mechanisms. In this study, we have used bicarbonate as a mobile exogenous proton-transfer reagent to recover the activity lost by site-directed mutations in order to identify amino-acid residues participating in the proton-transfer pathway. We find that bicarbonate restores efficient S-state cycling in D2-K317A PSII core complexes, but not in D1-D61A and CP43-R357K PSII core complexes, indicating that bicarbonate chemical rescue can be used to differentiate single-point mutations affecting the pathways of proton transfer from mutations that affect other aspects of the water-oxidation mechanism.
| Original language | English |
|---|---|
| Pages (from-to) | 611-617 |
| Number of pages | 7 |
| Journal | Biochimica et Biophysica Acta - Bioenergetics |
| Volume | 1860 |
| Issue number | 8 |
| DOIs | |
| Publication status | Published - Aug 1 2019 |
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Keywords
- Bicarbonate
- Oxygen evolution
- Photosystem II
- Proton transfer
- Water oxidation
ASJC Scopus subject areas
- Biophysics
- Biochemistry
- Cell Biology
Cite this
Bicarbonate rescues damaged proton-transfer pathway in photosystem II. / Banerjee, Gourab; Ghosh, Ipsita; Kim, Christopher J.; Debus, Richard J.; Brudvig, Gary W.
In: Biochimica et Biophysica Acta - Bioenergetics, Vol. 1860, No. 8, 01.08.2019, p. 611-617.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Bicarbonate rescues damaged proton-transfer pathway in photosystem II
AU - Banerjee, Gourab
AU - Ghosh, Ipsita
AU - Kim, Christopher J.
AU - Debus, Richard J.
AU - Brudvig, Gary W
PY - 2019/8/1
Y1 - 2019/8/1
N2 - The membrane-protein complex photosystem II (PSII) catalyzes photosynthetic water oxidation. Proton transfer plays an integral role in the catalytic cycle of water oxidation by maintaining charge balance to regulate and ensure the efficiency of the process. The hydrogen-bonded amino-acid residues that surround the oxygen-evolving complex (OEC) provide an efficient pathway for proton removal. Hence, it is crucial to identify these pathways to provide deeper insights into the proton-transfer mechanisms. In this study, we have used bicarbonate as a mobile exogenous proton-transfer reagent to recover the activity lost by site-directed mutations in order to identify amino-acid residues participating in the proton-transfer pathway. We find that bicarbonate restores efficient S-state cycling in D2-K317A PSII core complexes, but not in D1-D61A and CP43-R357K PSII core complexes, indicating that bicarbonate chemical rescue can be used to differentiate single-point mutations affecting the pathways of proton transfer from mutations that affect other aspects of the water-oxidation mechanism.
AB - The membrane-protein complex photosystem II (PSII) catalyzes photosynthetic water oxidation. Proton transfer plays an integral role in the catalytic cycle of water oxidation by maintaining charge balance to regulate and ensure the efficiency of the process. The hydrogen-bonded amino-acid residues that surround the oxygen-evolving complex (OEC) provide an efficient pathway for proton removal. Hence, it is crucial to identify these pathways to provide deeper insights into the proton-transfer mechanisms. In this study, we have used bicarbonate as a mobile exogenous proton-transfer reagent to recover the activity lost by site-directed mutations in order to identify amino-acid residues participating in the proton-transfer pathway. We find that bicarbonate restores efficient S-state cycling in D2-K317A PSII core complexes, but not in D1-D61A and CP43-R357K PSII core complexes, indicating that bicarbonate chemical rescue can be used to differentiate single-point mutations affecting the pathways of proton transfer from mutations that affect other aspects of the water-oxidation mechanism.
KW - Bicarbonate
KW - Oxygen evolution
KW - Photosystem II
KW - Proton transfer
KW - Water oxidation
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U2 - 10.1016/j.bbabio.2019.06.014
DO - 10.1016/j.bbabio.2019.06.014
M3 - Article
VL - 1860
SP - 611
EP - 617
JO - Biochimica et Biophysica Acta - Bioenergetics
JF - Biochimica et Biophysica Acta - Bioenergetics
SN - 0005-2728
IS - 8
ER -