Singlet oxygen production by photosystem II is caused by misses of the oxygen evolving complex
© 2022 The Authors. New Phytologist © 2022 New Phytologist Foundation.
| Veröffentlicht in: | The New phytologist. - 1979. - 237(2023), 1 vom: 05. Jan., Seite 113-125 |
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| 1. Verfasser: | |
| Weitere Verfasser: | , , |
| Format: | Online-Aufsatz |
| Sprache: | English |
| Veröffentlicht: |
2023
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| Zugriff auf das übergeordnete Werk: | The New phytologist |
| Schlagworte: | Journal Article Research Support, Non-U.S. Gov't FV/FM anaerobic anoxia cyanobacteria histidine photodamage reactive oxygen species Photosystem II Protein Complex mehr... |
| Zusammenfassung: | © 2022 The Authors. New Phytologist © 2022 New Phytologist Foundation. Singlet oxygen (1 O2 ) is a harmful species that functions also as a signaling molecule. In chloroplasts, 1 O2 is produced via charge recombination reactions in photosystem II, but which recombination pathway(s) produce triplet Chl and 1 O2 remains open. Furthermore, the role of 1 O2 in photoinhibition is not clear. We compared temperature dependences of 1 O2 production, photoinhibition, and recombination pathways. 1 O2 production by pumpkin thylakoids increased from -2 to +35°C, ruling out recombination of the primary charge pair as a main contributor. S2 QA - or S2 QB - recombination pathways, in turn, had too steep temperature dependences. Instead, the temperature dependence of 1 O2 production matched that of misses (failures of the oxygen (O2 ) evolving complex to advance an S-state). Photoinhibition in vitro and in vivo (also in Synechocystis), and in the presence or absence of O2 , had the same temperature dependence, but ultraviolet (UV)-radiation-caused photoinhibition showed a weaker temperature response. We suggest that the miss-associated recombination of P680 + QA - is the main producer of 1 O2 . Our results indicate three parallel photoinhibition mechanisms. The manganese mechanism dominates in UV radiation but also functions in white light. Mechanisms that depend on light absorption by Chls, having 1 O2 or long-lived P680 + as damaging agents, dominate in red light |
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| Beschreibung: | Date Completed 07.12.2022 Date Revised 15.04.2023 published: Print-Electronic Citation Status MEDLINE |
| ISSN: | 1469-8137 |
| DOI: | 10.1111/nph.18514 |