Electron paramagnetic resonance of the primary radical pair [D-center dot+Phi(A)(center dot-)] in reaction centers of photosynthetic bacteria
Using continuous wave EPR spectroscopy with a high time resolution, a new short-lived signal at g=2 is observed in bacterial photosynthetic reaction centers in which electron transfer past the bacteriopheophytin ΦA is blocked. This signal decays with a time constant equal to the rise time of the tri...
| Main Authors: | , , , , , |
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| Format: | Journal article |
| Language: | English |
| Published: |
1996
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| _version_ | 1797073257711534080 |
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| author | Proskuryakov, I Klenina, I Hore, P Bosch, M Gast, P Hoff, A |
| author_facet | Proskuryakov, I Klenina, I Hore, P Bosch, M Gast, P Hoff, A |
| author_sort | Proskuryakov, I |
| collection | OXFORD |
| description | Using continuous wave EPR spectroscopy with a high time resolution, a new short-lived signal at g=2 is observed in bacterial photosynthetic reaction centers in which electron transfer past the bacteriopheophytin ΦA is blocked. This signal decays with a time constant equal to the rise time of the triplet state of the primary donor 3D, and is therefore attributed to the primary radical pair [D·+ Φ·-A]. Applying the theory of spin-correlated radical pairs, the spectrum could be satisfactorily simulated, yielding the following magnetic interaction parameters between D·+ and Φ·-A: exchange interaction JDΦ = -0.9 ± 0.1 mT and JDΦ = -1.7 ± 0.1 mT for reaction centers of Rhodobacter sphaeroides R26 and Rhodopseudomonas viridis, respectively, and an axial dipolar interaction DDΦ = -3.0 ± 0.5 mT for Rhodopseudomonas viridis. The implications of the magnitude and sign of the exchange parameters for the energetics of photosynthetic electron transfer are discussed. |
| first_indexed | 2024-03-06T23:19:32Z |
| format | Journal article |
| id | oxford-uuid:6844f973-bf65-44c4-92c5-3244a769b435 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-06T23:19:32Z |
| publishDate | 1996 |
| record_format | dspace |
| spelling | oxford-uuid:6844f973-bf65-44c4-92c5-3244a769b4352022-03-26T18:43:47ZElectron paramagnetic resonance of the primary radical pair [D-center dot+Phi(A)(center dot-)] in reaction centers of photosynthetic bacteriaJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:6844f973-bf65-44c4-92c5-3244a769b435EnglishSymplectic Elements at Oxford1996Proskuryakov, IKlenina, IHore, PBosch, MGast, PHoff, AUsing continuous wave EPR spectroscopy with a high time resolution, a new short-lived signal at g=2 is observed in bacterial photosynthetic reaction centers in which electron transfer past the bacteriopheophytin ΦA is blocked. This signal decays with a time constant equal to the rise time of the triplet state of the primary donor 3D, and is therefore attributed to the primary radical pair [D·+ Φ·-A]. Applying the theory of spin-correlated radical pairs, the spectrum could be satisfactorily simulated, yielding the following magnetic interaction parameters between D·+ and Φ·-A: exchange interaction JDΦ = -0.9 ± 0.1 mT and JDΦ = -1.7 ± 0.1 mT for reaction centers of Rhodobacter sphaeroides R26 and Rhodopseudomonas viridis, respectively, and an axial dipolar interaction DDΦ = -3.0 ± 0.5 mT for Rhodopseudomonas viridis. The implications of the magnitude and sign of the exchange parameters for the energetics of photosynthetic electron transfer are discussed. |
| spellingShingle | Proskuryakov, I Klenina, I Hore, P Bosch, M Gast, P Hoff, A Electron paramagnetic resonance of the primary radical pair [D-center dot+Phi(A)(center dot-)] in reaction centers of photosynthetic bacteria |
| title | Electron paramagnetic resonance of the primary radical pair [D-center dot+Phi(A)(center dot-)] in reaction centers of photosynthetic bacteria |
| title_full | Electron paramagnetic resonance of the primary radical pair [D-center dot+Phi(A)(center dot-)] in reaction centers of photosynthetic bacteria |
| title_fullStr | Electron paramagnetic resonance of the primary radical pair [D-center dot+Phi(A)(center dot-)] in reaction centers of photosynthetic bacteria |
| title_full_unstemmed | Electron paramagnetic resonance of the primary radical pair [D-center dot+Phi(A)(center dot-)] in reaction centers of photosynthetic bacteria |
| title_short | Electron paramagnetic resonance of the primary radical pair [D-center dot+Phi(A)(center dot-)] in reaction centers of photosynthetic bacteria |
| title_sort | electron paramagnetic resonance of the primary radical pair d center dot phi a center dot in reaction centers of photosynthetic bacteria |
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