Energy Transfer and Radical-Pair Dynamics in Photosystem I with Different Red Chlorophyll <i>a</i> Pigments
We establish a general kinetic scheme for the energy transfer and radical-pair dynamics in photosystem I (PSI) of <i>Chlamydomonas reinhardtii</i>, <i>Synechocystis</i> PCC6803, <i>Thermosynechococcus elongatus</i> and <i>Spirulina platensis</i> grown...
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MDPI AG
2024-04-01
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| Series: | International Journal of Molecular Sciences |
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| Online Access: | https://www.mdpi.com/1422-0067/25/7/4125 |
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| author | Ivo H. M. van Stokkum Marc G. Müller Alfred R. Holzwarth |
| author_facet | Ivo H. M. van Stokkum Marc G. Müller Alfred R. Holzwarth |
| author_sort | Ivo H. M. van Stokkum |
| collection | DOAJ |
| description | We establish a general kinetic scheme for the energy transfer and radical-pair dynamics in photosystem I (PSI) of <i>Chlamydomonas reinhardtii</i>, <i>Synechocystis</i> PCC6803, <i>Thermosynechococcus elongatus</i> and <i>Spirulina platensis</i> grown under white-light conditions. With the help of simultaneous target analysis of transient-absorption data sets measured with two selective excitations, we resolved the spectral and kinetic properties of the different species present in PSI. WL-PSI can be described as a Bulk Chl <i>a</i> in equilibrium with a higher-energy Chl <i>a,</i> one or two Red Chl <i>a</i> and a reaction-center compartment (WL-RC). Three radical pairs (RPs) have been resolved with very similar properties in the four model organisms. The charge separation is virtually irreversible with a rate of ≈900 ns<sup>−1</sup>. The second rate, of RP1 → RP2, ranges from 70–90 ns<sup>−1</sup> and the third rate, of RP2 → RP3, is ≈30 ns<sup>−1</sup>. Since RP1 and the Red Chl <i>a</i> are simultaneously present, resolving the RP1 properties is challenging. In <i>Chlamydomonas reinhardtii</i>, the excited WL-RC and Bulk Chl <i>a</i> compartments equilibrate with a lifetime of ≈0.28 ps, whereas the Red and the Bulk Chl <i>a</i> compartments equilibrate with a lifetime of ≈2.65 ps. We present a description of the thermodynamic properties of the model organisms at room temperature. |
| first_indexed | 2024-04-24T10:42:41Z |
| format | Article |
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| issn | 1661-6596 1422-0067 |
| language | English |
| last_indexed | 2024-04-24T10:42:41Z |
| publishDate | 2024-04-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | International Journal of Molecular Sciences |
| spelling | doaj.art-d0119cf8b3bb4879a240c98be998bd832024-04-12T13:20:43ZengMDPI AGInternational Journal of Molecular Sciences1661-65961422-00672024-04-01257412510.3390/ijms25074125Energy Transfer and Radical-Pair Dynamics in Photosystem I with Different Red Chlorophyll <i>a</i> PigmentsIvo H. M. van Stokkum0Marc G. Müller1Alfred R. Holzwarth2Department of Physics and Astronomy and LaserLaB, Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The NetherlandsMax-Planck-Institut für Chemische Energiekonversion, D-45470 Mülheim a.d. Ruhr, GermanyDepartment of Physics and Astronomy and LaserLaB, Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The NetherlandsWe establish a general kinetic scheme for the energy transfer and radical-pair dynamics in photosystem I (PSI) of <i>Chlamydomonas reinhardtii</i>, <i>Synechocystis</i> PCC6803, <i>Thermosynechococcus elongatus</i> and <i>Spirulina platensis</i> grown under white-light conditions. With the help of simultaneous target analysis of transient-absorption data sets measured with two selective excitations, we resolved the spectral and kinetic properties of the different species present in PSI. WL-PSI can be described as a Bulk Chl <i>a</i> in equilibrium with a higher-energy Chl <i>a,</i> one or two Red Chl <i>a</i> and a reaction-center compartment (WL-RC). Three radical pairs (RPs) have been resolved with very similar properties in the four model organisms. The charge separation is virtually irreversible with a rate of ≈900 ns<sup>−1</sup>. The second rate, of RP1 → RP2, ranges from 70–90 ns<sup>−1</sup> and the third rate, of RP2 → RP3, is ≈30 ns<sup>−1</sup>. Since RP1 and the Red Chl <i>a</i> are simultaneously present, resolving the RP1 properties is challenging. In <i>Chlamydomonas reinhardtii</i>, the excited WL-RC and Bulk Chl <i>a</i> compartments equilibrate with a lifetime of ≈0.28 ps, whereas the Red and the Bulk Chl <i>a</i> compartments equilibrate with a lifetime of ≈2.65 ps. We present a description of the thermodynamic properties of the model organisms at room temperature.https://www.mdpi.com/1422-0067/25/7/4125photosynthesistarget analysistransient absorptionultrafast spectroscopy |
| spellingShingle | Ivo H. M. van Stokkum Marc G. Müller Alfred R. Holzwarth Energy Transfer and Radical-Pair Dynamics in Photosystem I with Different Red Chlorophyll <i>a</i> Pigments International Journal of Molecular Sciences photosynthesis target analysis transient absorption ultrafast spectroscopy |
| title | Energy Transfer and Radical-Pair Dynamics in Photosystem I with Different Red Chlorophyll <i>a</i> Pigments |
| title_full | Energy Transfer and Radical-Pair Dynamics in Photosystem I with Different Red Chlorophyll <i>a</i> Pigments |
| title_fullStr | Energy Transfer and Radical-Pair Dynamics in Photosystem I with Different Red Chlorophyll <i>a</i> Pigments |
| title_full_unstemmed | Energy Transfer and Radical-Pair Dynamics in Photosystem I with Different Red Chlorophyll <i>a</i> Pigments |
| title_short | Energy Transfer and Radical-Pair Dynamics in Photosystem I with Different Red Chlorophyll <i>a</i> Pigments |
| title_sort | energy transfer and radical pair dynamics in photosystem i with different red chlorophyll i a i pigments |
| topic | photosynthesis target analysis transient absorption ultrafast spectroscopy |
| url | https://www.mdpi.com/1422-0067/25/7/4125 |
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