A Unique LHCE Light-Harvesting protein Family is involved in Photosystem I and II Far-Red Absorption in Euglena gracilis
© The Author(s) 2025. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For commercial re-use, please contact reprintsoup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink serv...
| Veröffentlicht in: | Journal of experimental botany. - 1985. - (2025) vom: 08. Sept. |
|---|---|
| 1. Verfasser: | |
| Weitere Verfasser: | , , , , , , , , , , , , , |
| Format: | Online-Aufsatz |
| Sprache: | English |
| Veröffentlicht: |
2025
|
| Zugriff auf das übergeordnete Werk: | Journal of experimental botany |
| Schlagworte: | Journal Article Euglena gracilis Light harvesting complex Photoacclimation Photosystems far-red antenna light capture |
| Zusammenfassung: | © The Author(s) 2025. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For commercial re-use, please contact reprintsoup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com. Photosynthetic organisms have evolved diverse strategies to adapt to fluctuating light conditions, balancing efficient light capture with photoprotection. In green algae and land plants, this involves specialized light-harvesting complexes (LHCs), non-photochemical quenching, and state transitions driven by dynamic remodeling of antenna proteins associated with Photosystems (PS) I and II. Euglena gracilis, a flagellate with a secondary green plastid, represents a distantly related lineage whose light-harvesting regulation remains poorly understood. Although spectral shifts under different light regimes have been observed, their molecular basis was unknown. Here, through integrated phylogenomic, proteomic, structural, and spectroscopic analyses, we identify a novel chlorophyll a far-red-absorbing antenna complex in E. gracilis, composed of a species-specific Lhce protein family. This antenna forms a pentameric complex under low light and transiently associates with PSII during far-red light exposure. It is structurally and functionally distinct from canonical LHCII₃ trimers and absent in Viridiplantae. Additionally, PSI in E. gracilis is surrounded by an expanded Lhce/LhcbM belt around a minimal core. These findings reveal a unique mechanism for regulating PS antenna size in E. gracilis, distinct from known models in plants and green algae, and highlight an alternative evolutionary strategy for light acclimation in organisms with secondary plastids |
|---|---|
| Beschreibung: | Date Revised 08.09.2025 published: Print-Electronic Citation Status Publisher |
| ISSN: | 1460-2431 |
| DOI: | 10.1093/jxb/eraf383 |