Excitation Energy Transfer Dynamics from Carotenoid to Bacteriochlorophyll <i>a</i> in the LH2 Complex of <i>Rhodobacter sphaeroides</i>: Insights from Reconstitution Experiments with Carotenoids and B800 Bacteriochlorophyll <i>a</i>
Carotenoids are crucial for photosynthesis, playing key roles in light harvesting and photoprotection. In this study, spheroidene and bacteriochlorophyll <i>a</i> (Bchl <i>a</i>) were reconstituted into the chromatophores of the carotenoidless mutant <i>Rhodobacter spha...
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2025-02-01
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| author | Chiasa Uragami Marina Yoshida Alastair T. Gardiner Richard J. Cogdell Hideki Hashimoto |
| author_facet | Chiasa Uragami Marina Yoshida Alastair T. Gardiner Richard J. Cogdell Hideki Hashimoto |
| author_sort | Chiasa Uragami |
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| description | Carotenoids are crucial for photosynthesis, playing key roles in light harvesting and photoprotection. In this study, spheroidene and bacteriochlorophyll <i>a</i> (Bchl <i>a</i>) were reconstituted into the chromatophores of the carotenoidless mutant <i>Rhodobacter sphaeroides</i> R26.1, resulting in the preparation of high-quality LH2 complexes. Global and target analyses of transient absorption data revealed that incorporating B800 Bchl <i>a</i> significantly enhances excitation energy transfer (EET) efficiency from carotenoids to Bchl <i>a</i>. EET predominantly occurs from the carotenoid S<sub>2</sub> state, with additional pathways from the S<sub>1</sub> state observed in native LH2. Unique relaxation dynamics were identified, including the generation of the carotenoid S* state in reconstituted LH2 with both spheroidene and B800 Bchl <i>a</i> and the formation of the carotenoid T<sub>1</sub> state in reconstituted LH2. These findings underscore the critical influence of pigment composition and spatial organization on energy transfer mechanisms. They provide valuable insights into the molecular interplay that governs excitation energy transfer in photosynthetic light-harvesting systems. |
| format | Article |
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| language | English |
| publishDate | 2025-02-01 |
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| spelling | doaj-art-0351e02b5adc4cc4ac550e48ffe829d82025-08-20T02:04:06ZengMDPI AGMolecules1420-30492025-02-0130481410.3390/molecules30040814Excitation Energy Transfer Dynamics from Carotenoid to Bacteriochlorophyll <i>a</i> in the LH2 Complex of <i>Rhodobacter sphaeroides</i>: Insights from Reconstitution Experiments with Carotenoids and B800 Bacteriochlorophyll <i>a</i>Chiasa Uragami0Marina Yoshida1Alastair T. Gardiner2Richard J. Cogdell3Hideki Hashimoto4Department of Applied Chemistry for Environment, Graduate School of Science and Technology, Kwansei Gakuin University, 1 Gakuen-Uegahara, Sanda 669-1330, JapanDepartment of Applied Chemistry for Environment, Graduate School of Science and Technology, Kwansei Gakuin University, 1 Gakuen-Uegahara, Sanda 669-1330, JapanInstitute of Microbiology, Czech Academy of Sciences, 379 81 Trebon, Czech RepublicSchool of Molecular Biosciences, University of Glasgow, Glasgow G12 8QQ, UKDepartment of Applied Chemistry for Environment, Graduate School of Science and Technology, Kwansei Gakuin University, 1 Gakuen-Uegahara, Sanda 669-1330, JapanCarotenoids are crucial for photosynthesis, playing key roles in light harvesting and photoprotection. In this study, spheroidene and bacteriochlorophyll <i>a</i> (Bchl <i>a</i>) were reconstituted into the chromatophores of the carotenoidless mutant <i>Rhodobacter sphaeroides</i> R26.1, resulting in the preparation of high-quality LH2 complexes. Global and target analyses of transient absorption data revealed that incorporating B800 Bchl <i>a</i> significantly enhances excitation energy transfer (EET) efficiency from carotenoids to Bchl <i>a</i>. EET predominantly occurs from the carotenoid S<sub>2</sub> state, with additional pathways from the S<sub>1</sub> state observed in native LH2. Unique relaxation dynamics were identified, including the generation of the carotenoid S* state in reconstituted LH2 with both spheroidene and B800 Bchl <i>a</i> and the formation of the carotenoid T<sub>1</sub> state in reconstituted LH2. These findings underscore the critical influence of pigment composition and spatial organization on energy transfer mechanisms. They provide valuable insights into the molecular interplay that governs excitation energy transfer in photosynthetic light-harvesting systems.https://www.mdpi.com/1420-3049/30/4/814purple photosynthetic bacterialight-harvestingphotoprotectioncarotenoidB800 bacteriochlorophyll <i>a</i>reconstitution |
| spellingShingle | Chiasa Uragami Marina Yoshida Alastair T. Gardiner Richard J. Cogdell Hideki Hashimoto Excitation Energy Transfer Dynamics from Carotenoid to Bacteriochlorophyll <i>a</i> in the LH2 Complex of <i>Rhodobacter sphaeroides</i>: Insights from Reconstitution Experiments with Carotenoids and B800 Bacteriochlorophyll <i>a</i> Molecules purple photosynthetic bacteria light-harvesting photoprotection carotenoid B800 bacteriochlorophyll <i>a</i> reconstitution |
| title | Excitation Energy Transfer Dynamics from Carotenoid to Bacteriochlorophyll <i>a</i> in the LH2 Complex of <i>Rhodobacter sphaeroides</i>: Insights from Reconstitution Experiments with Carotenoids and B800 Bacteriochlorophyll <i>a</i> |
| title_full | Excitation Energy Transfer Dynamics from Carotenoid to Bacteriochlorophyll <i>a</i> in the LH2 Complex of <i>Rhodobacter sphaeroides</i>: Insights from Reconstitution Experiments with Carotenoids and B800 Bacteriochlorophyll <i>a</i> |
| title_fullStr | Excitation Energy Transfer Dynamics from Carotenoid to Bacteriochlorophyll <i>a</i> in the LH2 Complex of <i>Rhodobacter sphaeroides</i>: Insights from Reconstitution Experiments with Carotenoids and B800 Bacteriochlorophyll <i>a</i> |
| title_full_unstemmed | Excitation Energy Transfer Dynamics from Carotenoid to Bacteriochlorophyll <i>a</i> in the LH2 Complex of <i>Rhodobacter sphaeroides</i>: Insights from Reconstitution Experiments with Carotenoids and B800 Bacteriochlorophyll <i>a</i> |
| title_short | Excitation Energy Transfer Dynamics from Carotenoid to Bacteriochlorophyll <i>a</i> in the LH2 Complex of <i>Rhodobacter sphaeroides</i>: Insights from Reconstitution Experiments with Carotenoids and B800 Bacteriochlorophyll <i>a</i> |
| title_sort | excitation energy transfer dynamics from carotenoid to bacteriochlorophyll i a i in the lh2 complex of i rhodobacter sphaeroides i insights from reconstitution experiments with carotenoids and b800 bacteriochlorophyll i a i |
| topic | purple photosynthetic bacteria light-harvesting photoprotection carotenoid B800 bacteriochlorophyll <i>a</i> reconstitution |
| url | https://www.mdpi.com/1420-3049/30/4/814 |
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