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Influence of protein phosphorylation on the electron-transport properties of Photosystem II

Mamedov, Fikret LU ; Rintamaki, Eevi; Aro, Eva-Mari; Andersson, Bertil and Styring, Stenbjörn LU (2002) In Photosynthesis Research 74(1). p.61-72
Abstract
Many of the core proteins in Photosystem II (PS II) undergo reversible phosphorylation. It is known that protein phosphorylation controls the repair cycle of Photosystem II. However, it is not known how protein phosphorylation affects the partial electron transport reactions in PS II. Here we have applied variable fluorescence measurements and EPR spectroscopy to probe the status of the quinone acceptors, the Mn cluster and other electron transfer components in PS II with controlled levels of protein phosphorylation. Protein phosphorylation was induced in vivo by varying illumination regimes. The phosphorylation level of the D1 protein varied from 10 to 58% in PS II membranes isolated from pre-illuminated spinach leaves. The oxygen... (More)
Many of the core proteins in Photosystem II (PS II) undergo reversible phosphorylation. It is known that protein phosphorylation controls the repair cycle of Photosystem II. However, it is not known how protein phosphorylation affects the partial electron transport reactions in PS II. Here we have applied variable fluorescence measurements and EPR spectroscopy to probe the status of the quinone acceptors, the Mn cluster and other electron transfer components in PS II with controlled levels of protein phosphorylation. Protein phosphorylation was induced in vivo by varying illumination regimes. The phosphorylation level of the D1 protein varied from 10 to 58% in PS II membranes isolated from pre-illuminated spinach leaves. The oxygen evolution and Q A- to Q B(Q B-) electron transfer measured by flash-induced fluorescence decay remained similar in all samples studied. Similar measurements in the presence of DCMU, which reports on the status of the donor side in PS II, also indicated that the integrity of the oxygen-evolving complex was preserved in PS II with different levels of D1 protein phosphorylation. With EPR spectroscopy we examined individual redox cofactors in PS II. Both the maximal amplitude of the charge separation reaction (measured as photo-accumulated pheophytin-) and the EPR signal from the Q A- Fe2+ complex were unaffected by the phosphorylation of the D1 protein, indicating that the acceptor side of PS II was not modified. Also the shape of the S2 state multiline signal was similar, suggesting that the structure of the Mn-cluster in Photosystem II did not change. However, the amplitude of the S2 multiline signal was reduced by 35% in PS II, where 58% of the D1 protein was phosphorylated, as compared to the S2 multiline in PS II, where only 10% of the D1 protein was phosphorylated. In addition, the fraction of low potential Cyt b559 was twice as high in phosphorylated PS II. Implications from these findings, were precise quantification of D1 protein phosphorylation is, for the first time, combined with high-resolution biophysical measurements, are discussed. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
electron transport, EPR, fluorescence, Photosystem II, protein phosphorylation
in
Photosynthesis Research
volume
74
issue
1
pages
61 - 72
publisher
Springer
external identifiers
  • wos:000178933000005
  • scopus:0036438646
ISSN
0166-8595
DOI
10.1023/A:1020835822266
language
English
LU publication?
yes
id
4103eda6-97a4-45fe-8b8c-d30ec247d415 (old id 124840)
date added to LUP
2007-07-06 11:54:23
date last changed
2017-07-23 04:39:00
@article{4103eda6-97a4-45fe-8b8c-d30ec247d415,
  abstract     = {Many of the core proteins in Photosystem II (PS II) undergo reversible phosphorylation. It is known that protein phosphorylation controls the repair cycle of Photosystem II. However, it is not known how protein phosphorylation affects the partial electron transport reactions in PS II. Here we have applied variable fluorescence measurements and EPR spectroscopy to probe the status of the quinone acceptors, the Mn cluster and other electron transfer components in PS II with controlled levels of protein phosphorylation. Protein phosphorylation was induced in vivo by varying illumination regimes. The phosphorylation level of the D1 protein varied from 10 to 58% in PS II membranes isolated from pre-illuminated spinach leaves. The oxygen evolution and Q A- to Q B(Q B-) electron transfer measured by flash-induced fluorescence decay remained similar in all samples studied. Similar measurements in the presence of DCMU, which reports on the status of the donor side in PS II, also indicated that the integrity of the oxygen-evolving complex was preserved in PS II with different levels of D1 protein phosphorylation. With EPR spectroscopy we examined individual redox cofactors in PS II. Both the maximal amplitude of the charge separation reaction (measured as photo-accumulated pheophytin-) and the EPR signal from the Q A- Fe2+ complex were unaffected by the phosphorylation of the D1 protein, indicating that the acceptor side of PS II was not modified. Also the shape of the S2 state multiline signal was similar, suggesting that the structure of the Mn-cluster in Photosystem II did not change. However, the amplitude of the S2 multiline signal was reduced by 35% in PS II, where 58% of the D1 protein was phosphorylated, as compared to the S2 multiline in PS II, where only 10% of the D1 protein was phosphorylated. In addition, the fraction of low potential Cyt b559 was twice as high in phosphorylated PS II. Implications from these findings, were precise quantification of D1 protein phosphorylation is, for the first time, combined with high-resolution biophysical measurements, are discussed.},
  author       = {Mamedov, Fikret and Rintamaki, Eevi and Aro, Eva-Mari and Andersson, Bertil and Styring, Stenbjörn},
  issn         = {0166-8595},
  keyword      = {electron transport,EPR,fluorescence,Photosystem II,protein phosphorylation},
  language     = {eng},
  number       = {1},
  pages        = {61--72},
  publisher    = {Springer},
  series       = {Photosynthesis Research},
  title        = {Influence of protein phosphorylation on the electron-transport properties of Photosystem II},
  url          = {http://dx.doi.org/10.1023/A:1020835822266},
  volume       = {74},
  year         = {2002},
}