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Enhancement of Y-D(center dot) spin relaxation by the CaMn4 cluster in photosystem II detected at room temperature: A new probe for the S-cycle

Ho, Felix M.; Morvaridi, Susan F LU ; Mamedov, Fikret LU and Styring, Stenbjörn LU (2007) In Biochimica et Biophysica Acta - Bioenergetics 1767(1). p.5-14
Abstract
The long-lived, light-induced radical Y-D(.) of the Tyr161 residue in the D2 protein of Photosystem 11 (PSII) is known to magnetically interact with the CaMn4 cluster, situated similar to 30 angstrom away. In this study we report a transient step-change increase in YD EPR intensity upon the application of a single laser flash to S, state-synchronised PSII-enriched membranes from spinach. This transient effect was observed at room temperature and high applied microwave power (100 mW) in samples containing PpBQ, as well as those containing DCMU. The subsequent decay lifetimes were found to differ depending on the additive used. We propose that this flash-induced signal increase was caused by enhanced spin relaxation of YD by the OEC in the... (More)
The long-lived, light-induced radical Y-D(.) of the Tyr161 residue in the D2 protein of Photosystem 11 (PSII) is known to magnetically interact with the CaMn4 cluster, situated similar to 30 angstrom away. In this study we report a transient step-change increase in YD EPR intensity upon the application of a single laser flash to S, state-synchronised PSII-enriched membranes from spinach. This transient effect was observed at room temperature and high applied microwave power (100 mW) in samples containing PpBQ, as well as those containing DCMU. The subsequent decay lifetimes were found to differ depending on the additive used. We propose that this flash-induced signal increase was caused by enhanced spin relaxation of YD by the OEC in the S-2 state, as a consequence of the single laser flash turnover. The post-flash decay reflected S-2 -> S-1 back-turnover, as confirmed by their correlations with independent measurements of S-2 multiline EPR signal and flash-induced variable fluorescence decay kinetics under corresponding experimental conditions. This flash-induced effect opens up the possibility to study the kinetic behaviour of S-state transitions at room temperature using YD as a probe. (c) 2006 Elsevier B.Z. All rights reserved. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
S-state transitions, oxygen evolving complex, photosystem II, EPR, tyrosine D, spin relaxation
in
Biochimica et Biophysica Acta - Bioenergetics
volume
1767
issue
1
pages
5 - 14
publisher
Elsevier
external identifiers
  • wos:000243983500001
  • scopus:33846222013
ISSN
0005-2728
DOI
10.1016/j.bbabio.2006.08.006
language
English
LU publication?
yes
id
77f5a801-0a75-432b-96fa-329e3e91775f (old id 675301)
date added to LUP
2007-12-12 14:21:05
date last changed
2017-01-01 06:52:25
@article{77f5a801-0a75-432b-96fa-329e3e91775f,
  abstract     = {The long-lived, light-induced radical Y-D(.) of the Tyr161 residue in the D2 protein of Photosystem 11 (PSII) is known to magnetically interact with the CaMn4 cluster, situated similar to 30 angstrom away. In this study we report a transient step-change increase in YD EPR intensity upon the application of a single laser flash to S, state-synchronised PSII-enriched membranes from spinach. This transient effect was observed at room temperature and high applied microwave power (100 mW) in samples containing PpBQ, as well as those containing DCMU. The subsequent decay lifetimes were found to differ depending on the additive used. We propose that this flash-induced signal increase was caused by enhanced spin relaxation of YD by the OEC in the S-2 state, as a consequence of the single laser flash turnover. The post-flash decay reflected S-2 -> S-1 back-turnover, as confirmed by their correlations with independent measurements of S-2 multiline EPR signal and flash-induced variable fluorescence decay kinetics under corresponding experimental conditions. This flash-induced effect opens up the possibility to study the kinetic behaviour of S-state transitions at room temperature using YD as a probe. (c) 2006 Elsevier B.Z. All rights reserved.},
  author       = {Ho, Felix M. and Morvaridi, Susan F and Mamedov, Fikret and Styring, Stenbjörn},
  issn         = {0005-2728},
  keyword      = {S-state transitions,oxygen evolving complex,photosystem II,EPR,tyrosine D,spin relaxation},
  language     = {eng},
  number       = {1},
  pages        = {5--14},
  publisher    = {Elsevier},
  series       = {Biochimica et Biophysica Acta - Bioenergetics},
  title        = {Enhancement of Y-D(center dot) spin relaxation by the CaMn4 cluster in photosystem II detected at room temperature: A new probe for the S-cycle},
  url          = {http://dx.doi.org/10.1016/j.bbabio.2006.08.006},
  volume       = {1767},
  year         = {2007},
}