Visible light induction of an electron paramagnetic resonance split signal in photosystem II in the S 2 state reveals the importance of charges in the oxygen-evolving center during catalysis : A unifying model
(2012) In Biochemistry 51(10). p.2054-2064- Abstract
Cryogenic illumination of Photosystem II (PSII) can lead to the trapping of the metastable radical Y Z •, the radical form of the redox-active tyrosine residue D1-Tyr161 (known as Y Z). Magnetic interaction between this radical and the CaMn 4 cluster of PSII gives rise to so-called split electron paramagnetic resonance (EPR) signals with characteristics that are dependent on the S state. We report here the observation and characterization of a split EPR signal that can be directly induced from PSII centers in the S 2 state through visible light illumination at 10 K. We further show that the induction of this split signal takes place via a Mn-centered mechanism, in the same way as... (More)
Cryogenic illumination of Photosystem II (PSII) can lead to the trapping of the metastable radical Y Z •, the radical form of the redox-active tyrosine residue D1-Tyr161 (known as Y Z). Magnetic interaction between this radical and the CaMn 4 cluster of PSII gives rise to so-called split electron paramagnetic resonance (EPR) signals with characteristics that are dependent on the S state. We report here the observation and characterization of a split EPR signal that can be directly induced from PSII centers in the S 2 state through visible light illumination at 10 K. We further show that the induction of this split signal takes place via a Mn-centered mechanism, in the same way as when using near-infrared light illumination [Koulougliotis, D., et al. (2003) Biochemistry 42, 3045-3053]. On the basis of interpretations of these results, and in combination with literature data for other split signals induced under a variety of conditions (temperature and light quality), we propose a unified model for the mechanisms of split signal induction across the four S states (S 0, S 1, S 2, and S 3). At the heart of this model is the stability or instability of the Y Z •(D1-His190) + pair that would be formed during cryogenic oxidation of Y Z. Furthermore, the model is closely related to the sequence of transfers of protons and electrons from the CaMn 4 cluster during the S cycle and further demonstrates the utility of the split signals in probing the immediate environment of the oxygen-evolving center in PSII.
(Less)
- author
- Sjöholm, Johannes ; Styring, Stenbjörn LU ; Havelius, Kajsa G.V. LU and Ho, Felix M.
- publishing date
- 2012-03-13
- type
- Contribution to journal
- publication status
- published
- in
- Biochemistry
- volume
- 51
- issue
- 10
- pages
- 11 pages
- publisher
- The American Chemical Society (ACS)
- external identifiers
-
- scopus:84858221074
- pmid:22352968
- ISSN
- 0006-2960
- DOI
- 10.1021/bi2015794
- language
- English
- LU publication?
- no
- id
- 59d849a3-d80b-4823-88ec-d5fb035e9b16
- date added to LUP
- 2020-01-15 10:19:46
- date last changed
- 2024-05-15 05:43:07
@article{59d849a3-d80b-4823-88ec-d5fb035e9b16,
abstract = {{<p>Cryogenic illumination of Photosystem II (PSII) can lead to the trapping of the metastable radical Y <sub>Z</sub> <sup>•</sup>, the radical form of the redox-active tyrosine residue D1-Tyr161 (known as Y <sub>Z</sub>). Magnetic interaction between this radical and the CaMn <sub>4</sub> cluster of PSII gives rise to so-called split electron paramagnetic resonance (EPR) signals with characteristics that are dependent on the S state. We report here the observation and characterization of a split EPR signal that can be directly induced from PSII centers in the S <sub>2</sub> state through visible light illumination at 10 K. We further show that the induction of this split signal takes place via a Mn-centered mechanism, in the same way as when using near-infrared light illumination [Koulougliotis, D., et al. (2003) Biochemistry 42, 3045-3053]. On the basis of interpretations of these results, and in combination with literature data for other split signals induced under a variety of conditions (temperature and light quality), we propose a unified model for the mechanisms of split signal induction across the four S states (S <sub>0</sub>, S <sub>1</sub>, S <sub>2</sub>, and S <sub>3</sub>). At the heart of this model is the stability or instability of the Y <sub>Z</sub> <sup>•</sup>(D1-His190) <sup>+</sup> pair that would be formed during cryogenic oxidation of Y <sub>Z</sub>. Furthermore, the model is closely related to the sequence of transfers of protons and electrons from the CaMn <sub>4</sub> cluster during the S cycle and further demonstrates the utility of the split signals in probing the immediate environment of the oxygen-evolving center in PSII.</p>}},
author = {{Sjöholm, Johannes and Styring, Stenbjörn and Havelius, Kajsa G.V. and Ho, Felix M.}},
issn = {{0006-2960}},
language = {{eng}},
month = {{03}},
number = {{10}},
pages = {{2054--2064}},
publisher = {{The American Chemical Society (ACS)}},
series = {{Biochemistry}},
title = {{Visible light induction of an electron paramagnetic resonance split signal in photosystem II in the S <sub>2</sub> state reveals the importance of charges in the oxygen-evolving center during catalysis : A unifying model}},
url = {{http://dx.doi.org/10.1021/bi2015794}},
doi = {{10.1021/bi2015794}},
volume = {{51}},
year = {{2012}},
}