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Direct quantification of the four individual S states in Photosystem II using EPR spectroscopy

Han, Guangye ; Ho, Felix M. ; Havelius, Kajsa G.V. LU ; Morvaridi, Susan F. LU ; Mamedov, Fikret LU and Styring, Stenbjörn LU (2008) In Biochimica et Biophysica Acta - Bioenergetics 1777(6). p.496-503
Abstract

EPR spectroscopy is very useful in studies of the oxygen evolving cycle in Photosystem II and EPR signals from the CaMn4 cluster are known in all S states except S4. Many signals are insufficiently understood and the S0, S1, and S3 states have not yet been quantifiable through their EPR signals. Recently, split EPR signals, induced by illumination at liquid helium temperatures, have been reported in the S0, S1, and S3 states. These split signals provide new spectral probes to the S state chemistry. We have studied the flash power dependence of the S state turnover in Photosystem II membranes by monitoring the split S0, split S1,... (More)

EPR spectroscopy is very useful in studies of the oxygen evolving cycle in Photosystem II and EPR signals from the CaMn4 cluster are known in all S states except S4. Many signals are insufficiently understood and the S0, S1, and S3 states have not yet been quantifiable through their EPR signals. Recently, split EPR signals, induced by illumination at liquid helium temperatures, have been reported in the S0, S1, and S3 states. These split signals provide new spectral probes to the S state chemistry. We have studied the flash power dependence of the S state turnover in Photosystem II membranes by monitoring the split S0, split S1, split S3 and S2 state multiline EPR signals. We demonstrate that quantification of the S1, S3 and S0 states, using the split EPR signals, is indeed possible in samples with mixed S state composition. The amplitudes of all three split EPR signals are linearly correlated to the concentration of the respective S state. We also show that the S1 → S2 transition proceeds without misses following a saturating flash at 1 °C, whilst substantial misses occur in the S2 → S3 transition following the second flash.

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author
; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
keywords
EPR, Misses, Oxygen evolving complex, Photosystem II, S states, Split signals
in
Biochimica et Biophysica Acta - Bioenergetics
volume
1777
issue
6
pages
8 pages
publisher
Elsevier
external identifiers
  • pmid:18406339
  • scopus:44749086999
ISSN
0005-2728
DOI
10.1016/j.bbabio.2008.03.007
language
English
LU publication?
no
id
7e2d9139-a1ad-4729-9735-540f1803949a
date added to LUP
2020-01-15 10:32:18
date last changed
2024-10-02 20:16:29
@article{7e2d9139-a1ad-4729-9735-540f1803949a,
  abstract     = {{<p>EPR spectroscopy is very useful in studies of the oxygen evolving cycle in Photosystem II and EPR signals from the CaMn<sub>4</sub> cluster are known in all S states except S<sub>4</sub>. Many signals are insufficiently understood and the S<sub>0</sub>, S<sub>1</sub>, and S<sub>3</sub> states have not yet been quantifiable through their EPR signals. Recently, split EPR signals, induced by illumination at liquid helium temperatures, have been reported in the S<sub>0</sub>, S<sub>1</sub>, and S<sub>3</sub> states. These split signals provide new spectral probes to the S state chemistry. We have studied the flash power dependence of the S state turnover in Photosystem II membranes by monitoring the split S<sub>0</sub>, split S<sub>1</sub>, split S<sub>3</sub> and S<sub>2</sub> state multiline EPR signals. We demonstrate that quantification of the S<sub>1</sub>, S<sub>3</sub> and S<sub>0</sub> states, using the split EPR signals, is indeed possible in samples with mixed S state composition. The amplitudes of all three split EPR signals are linearly correlated to the concentration of the respective S state. We also show that the S<sub>1</sub> → S<sub>2</sub> transition proceeds without misses following a saturating flash at 1 °C, whilst substantial misses occur in the S<sub>2</sub> → S<sub>3</sub> transition following the second flash.</p>}},
  author       = {{Han, Guangye and Ho, Felix M. and Havelius, Kajsa G.V. and Morvaridi, Susan F. and Mamedov, Fikret and Styring, Stenbjörn}},
  issn         = {{0005-2728}},
  keywords     = {{EPR; Misses; Oxygen evolving complex; Photosystem II; S states; Split signals}},
  language     = {{eng}},
  month        = {{06}},
  number       = {{6}},
  pages        = {{496--503}},
  publisher    = {{Elsevier}},
  series       = {{Biochimica et Biophysica Acta - Bioenergetics}},
  title        = {{Direct quantification of the four individual S states in Photosystem II using EPR spectroscopy}},
  url          = {{http://dx.doi.org/10.1016/j.bbabio.2008.03.007}},
  doi          = {{10.1016/j.bbabio.2008.03.007}},
  volume       = {{1777}},
  year         = {{2008}},
}