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CryoEM PSII structure reveals adaptation mechanisms to environmental stress in Chlorella ohadii

Performing photosynthesis in the desert is a challenging task since it requires a fast adaptation to extreme illumination and temperature changes. To understand adaptive mechanisms, we purified Photosystem II (PSII) from Chlorella ohadii, a green alga from the desert soil surface, and identified str...

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Autores principales: Fadeeva, Maria, Klaiman, Daniel, Caspy, Ido, Nelson, Nathan
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Cold Spring Harbor Laboratory 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10187303/
https://www.ncbi.nlm.nih.gov/pubmed/37205566
http://dx.doi.org/10.1101/2023.05.04.539358
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author Fadeeva, Maria
Klaiman, Daniel
Caspy, Ido
Nelson, Nathan
author_facet Fadeeva, Maria
Klaiman, Daniel
Caspy, Ido
Nelson, Nathan
author_sort Fadeeva, Maria
collection PubMed
description Performing photosynthesis in the desert is a challenging task since it requires a fast adaptation to extreme illumination and temperature changes. To understand adaptive mechanisms, we purified Photosystem II (PSII) from Chlorella ohadii, a green alga from the desert soil surface, and identified structural elements that might enable the photosystem functioning under harsh conditions. The 2.72 Å cryogenic electron-microscopy (cryoEM) structure of PSII exhibited 64 subunits, encompassing 386 chlorophylls, 86 carotenoids, four plastoquinones, and several structural lipids. At the luminal side of PSII, the oxygen evolving complex was protected by a unique subunit arrangement - PsbO (OEE1), PsbP (OEE2), CP47, and PsbU (plant OEE3 homolog). PsbU interacted with PsbO, CP43, and PsbP, thus stabilising the oxygen evolving shield. Substantial changes were observed on the stromal electron acceptor side - PsbY was identified as a transmembrane helix situated alongside PsbF and PsbE enclosing cytochrome b559, supported by the adjacent C-terminal helix of Psb10. These four transmembrane helices bundled jointly, shielding cytochrome b559 from the solvent. The bulk of Psb10 formed a cap protecting the quinone site and probably contributed to the PSII stacking. So far, the C. ohadii PSII structure is the most complete description of the complex, suggesting numerous future experiments. A protective mechanism that prevented Q(B) from rendering itself fully reduced is proposed.
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spelling pubmed-101873032023-05-17 CryoEM PSII structure reveals adaptation mechanisms to environmental stress in Chlorella ohadii Fadeeva, Maria Klaiman, Daniel Caspy, Ido Nelson, Nathan bioRxiv Article Performing photosynthesis in the desert is a challenging task since it requires a fast adaptation to extreme illumination and temperature changes. To understand adaptive mechanisms, we purified Photosystem II (PSII) from Chlorella ohadii, a green alga from the desert soil surface, and identified structural elements that might enable the photosystem functioning under harsh conditions. The 2.72 Å cryogenic electron-microscopy (cryoEM) structure of PSII exhibited 64 subunits, encompassing 386 chlorophylls, 86 carotenoids, four plastoquinones, and several structural lipids. At the luminal side of PSII, the oxygen evolving complex was protected by a unique subunit arrangement - PsbO (OEE1), PsbP (OEE2), CP47, and PsbU (plant OEE3 homolog). PsbU interacted with PsbO, CP43, and PsbP, thus stabilising the oxygen evolving shield. Substantial changes were observed on the stromal electron acceptor side - PsbY was identified as a transmembrane helix situated alongside PsbF and PsbE enclosing cytochrome b559, supported by the adjacent C-terminal helix of Psb10. These four transmembrane helices bundled jointly, shielding cytochrome b559 from the solvent. The bulk of Psb10 formed a cap protecting the quinone site and probably contributed to the PSII stacking. So far, the C. ohadii PSII structure is the most complete description of the complex, suggesting numerous future experiments. A protective mechanism that prevented Q(B) from rendering itself fully reduced is proposed. Cold Spring Harbor Laboratory 2023-05-04 /pmc/articles/PMC10187303/ /pubmed/37205566 http://dx.doi.org/10.1101/2023.05.04.539358 Text en https://creativecommons.org/licenses/by-nd/4.0/This work is licensed under a Creative Commons Attribution-NoDerivatives 4.0 International License (https://creativecommons.org/licenses/by-nd/4.0/) , which allows reusers to copy and distribute the material in any medium or format in unadapted form only, and only so long as attribution is given to the creator. The license allows for commercial use.
spellingShingle Article
Fadeeva, Maria
Klaiman, Daniel
Caspy, Ido
Nelson, Nathan
CryoEM PSII structure reveals adaptation mechanisms to environmental stress in Chlorella ohadii
title CryoEM PSII structure reveals adaptation mechanisms to environmental stress in Chlorella ohadii
title_full CryoEM PSII structure reveals adaptation mechanisms to environmental stress in Chlorella ohadii
title_fullStr CryoEM PSII structure reveals adaptation mechanisms to environmental stress in Chlorella ohadii
title_full_unstemmed CryoEM PSII structure reveals adaptation mechanisms to environmental stress in Chlorella ohadii
title_short CryoEM PSII structure reveals adaptation mechanisms to environmental stress in Chlorella ohadii
title_sort cryoem psii structure reveals adaptation mechanisms to environmental stress in chlorella ohadii
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10187303/
https://www.ncbi.nlm.nih.gov/pubmed/37205566
http://dx.doi.org/10.1101/2023.05.04.539358
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