Stability of the S3 and S2 State Intermediates in Photosystem II Directly Probed by EPR Spectroscopy
| Autor: | Fikret Mamedov, Stenbjörn Styring, Erik Göransson, Guiying Chen, Guangye Han |
|---|---|
| Rok vydání: | 2011 |
| Předmět: |
chemistry.chemical_classification
0303 health sciences Photosystem II Photodissociation Analytical chemistry Oxygen-evolving complex Electron acceptor 010402 general chemistry 01 natural sciences Biochemistry Electron transport chain 0104 chemical sciences law.invention 03 medical and health sciences chemistry law Phase (matter) Thylakoid Electron paramagnetic resonance 030304 developmental biology |
| Zdroj: | Biochemistry. 51:138-148 |
| ISSN: | 1520-4995 0006-2960 |
| DOI: | 10.1021/bi200627j |
| Popis: | The stability of the S3 and S2 states of the oxygen evolving complex in photosystem II (PSII) was directly probed by EPR spectroscopy in PSII membrane preparations from spinach in the presence of the exogenous electron acceptor PpBQ at 1, 10, and 20 °C. The decay of the S3 state was followed in samples exposed to two flashes by measuring the split S3 EPR signal induced by near-infrared illumination at 5 K. The decay of the S2 state was followed in samples exposed to one flash by measuring the S2 state multiline EPR signal. During the decay of the S3 state, the S2 state multiline EPR signal first increased and then decreased in amplitude. This shows that the decay of the S3 state to the S1 state occurs via the S2 state. The decay of the S3 state was biexponential with a fast kinetic phase with a few seconds decay half-time. This occurred in 10–20% of the PSII centers. The slow kinetic phase ranged from a decay half-time of 700 s (at 1 °C) to ∼100 s (at 20 °C) in the remaining 80–90% of the centers. The dec... |
| Databáze: | OpenAIRE |
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