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pH-dependent oxidation of Cytochrome b559 is different in the different S-states

Morvaridi, Fatemeh; Feyziyev, Yashar LU ; Bernat, Gabor LU ; Geijer, Paulina LU ; Mamedov, Fikret LU and Styring, Stenbjörn LU (2001) In PS2001 Proceedings
Abstract
We have studied the state of Cyt b559 and the Mn cluster by EPR and optical spectroscopy in the different S-states between pH 4.0-10.0. In these experiments, the pH was changed after the OEC turnover to the appropriate S-state (at pH 6.0) by 0-3 saturating flashes. Furthermore, the state of Cyt b559 after a subsequent flash given after the pH modification was also investigated.

The results show that low (< pH 6.0) and high pH (> pH 9.0) resulted in an increase in the oxidized form of Cyt b559 in the S2 and S3 states. The effect was more pronounced at low than high pH. There was no further oxidation after the subsequent flash. Different to this, the pH induced oxidized Cyt b559 population in the S0 and S1 states was... (More)
We have studied the state of Cyt b559 and the Mn cluster by EPR and optical spectroscopy in the different S-states between pH 4.0-10.0. In these experiments, the pH was changed after the OEC turnover to the appropriate S-state (at pH 6.0) by 0-3 saturating flashes. Furthermore, the state of Cyt b559 after a subsequent flash given after the pH modification was also investigated.

The results show that low (< pH 6.0) and high pH (> pH 9.0) resulted in an increase in the oxidized form of Cyt b559 in the S2 and S3 states. The effect was more pronounced at low than high pH. There was no further oxidation after the subsequent flash. Different to this, the pH induced oxidized Cyt b559 population in the S0 and S1 states was significantly smaller. In the S1 state, the pH dependent oxidation of Cyt b559 was very weak, with a slight increase from pH 10.0 to 4.0. A subsequent flash in S0 or S1 resulted in a significant Cyt b559 oxidation at both low and high pH’s.

The ratio of the high and low potential forms of Cyt b559 at different pH’s was also different in different S-states. At low and normal pH’s both oxidized LP and HP forms were observed, while at high pH’s, only the LP form was oxidized. The possible involvement of Cyt b559 in electron donation to the Mn cluster during S-cycle at extreme pH is discussed. (Less)
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organization
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type
Chapter in Book/Report/Conference proceeding
publication status
published
subject
keywords
EPR, pH, Cytochrome b559, electron transfer, Photosystem II
in
PS2001 Proceedings
publisher
CSIRO Publishing
ISBN
CD-ROM - 0643067116
language
English
LU publication?
yes
id
21159dbf-9716-477a-8832-d5e176b01035 (old id 527307)
alternative location
http://www.publish.csiro.au/PS2001/cf/search/article.cfm?ID=453065714
date added to LUP
2007-09-24 09:03:28
date last changed
2016-04-16 10:27:29
@inproceedings{21159dbf-9716-477a-8832-d5e176b01035,
  abstract     = {We have studied the state of Cyt b559 and the Mn cluster by EPR and optical spectroscopy in the different S-states between pH 4.0-10.0. In these experiments, the pH was changed after the OEC turnover to the appropriate S-state (at pH 6.0) by 0-3 saturating flashes. Furthermore, the state of Cyt b559 after a subsequent flash given after the pH modification was also investigated.<br/><br>
The results show that low (&lt; pH 6.0) and high pH (&gt; pH 9.0) resulted in an increase in the oxidized form of Cyt b559 in the S2 and S3 states. The effect was more pronounced at low than high pH. There was no further oxidation after the subsequent flash. Different to this, the pH induced oxidized Cyt b559 population in the S0 and S1 states was significantly smaller. In the S1 state, the pH dependent oxidation of Cyt b559 was very weak, with a slight increase from pH 10.0 to 4.0. A subsequent flash in S0 or S1 resulted in a significant Cyt b559 oxidation at both low and high pH’s.<br/><br>
The ratio of the high and low potential forms of Cyt b559 at different pH’s was also different in different S-states. At low and normal pH’s both oxidized LP and HP forms were observed, while at high pH’s, only the LP form was oxidized. The possible involvement of Cyt b559 in electron donation to the Mn cluster during S-cycle at extreme pH is discussed.},
  author       = {Morvaridi, Fatemeh and Feyziyev, Yashar and Bernat, Gabor and Geijer, Paulina and Mamedov, Fikret and Styring, Stenbjörn},
  booktitle    = {PS2001 Proceedings},
  isbn         = {CD-ROM - 0643067116},
  keyword      = {EPR,pH,Cytochrome b559,electron transfer,Photosystem II},
  language     = {eng},
  publisher    = {CSIRO Publishing},
  title        = {pH-dependent oxidation of Cytochrome b559 is different in the different S-states},
  year         = {2001},
}