@article{59295208bb3e4a5da4c0dc47a3502a71,
title = "Structure of Dunaliella photosystem II reveals conformational flexibility of stacked and unstacked supercomplexes",
abstract = "Photosystem II (PSII) generates an oxidant whose redox potential is high enough to enable water oxidation, a substrate so abundant that it assures a practically unlimited electron source for life on earth. Our knowledge on the mechanism of water photooxidation was greatly advanced by high-resolution structures of prokaryotic PSII. Here, we show high-resolution cryogenic electron microscopy (cryo-EM) structures of eukaryotic PSII from the green alga Dunaliella salina at two distinct conformations. The conformers are also present in stacked PSII, exhibiting flexibility that may be relevant to the grana formation in chloroplasts of the green lineage. CP29, one of PSII associated light-harvesting antennae, plays a major role in distinguishing the two conformations of the supercomplex. We also show that the stacked PSII dimer, a form suggested to support the organisation of thylakoid membranes, can appear in many different orientations providing a flexible stacking mechanism for the arrangement of grana stacks in thylakoids. Our findings provide a structural basis for the heterogenous nature of the eukaryotic PSII on multiple levels.",
author = "Ido Caspy and Maria Fadeeva and Yuval Mazor and Nathan Nelson",
note = "Funding Information: Dr Yael Levi-Kalisman is gratefully acknowledged and thanked for vitrifying the samples. We also thank the Electron Microscopy Core Facility (EMCF) at the European Molecular Biology Laboratory (EMBL) for their support and Felix Weis for data collection and excellent technical support. Molecular graphics and analyses were performed with UCSF Chimera, developed by the Resource for Biocom-puting, Visualisation, and Informatics at the University of California, San Francisco, with support from NIH P41-GM103311. Molecular graphics and analyses performed with UCSF ChimeraX, developed by the Resource for Biocomputing, Visualisation, and Informatics at the University of California, San Francisco, with support from National Institutes of Health R01-GM129325 and the Office of Cyber Infrastructure and Computational Biology, National Institute of Allergy and Infectious Diseases. This work was supported by The Israel Science Foundation (Grants No. 569/17 and 199/21), and by German-Israeli Foundation for Scientific Research and Development (GIF), Grant no. G-1483-207/2018. Y.M acknowledges the support by the National Science Foundation under Award No. 2034021. Funding Information: Dr Yael Levi-Kalisman is gratefully acknowledged and thanked for vitrifying the samples. We also thank the Electron Microscopy Core Facility (EMCF) at the European Molecular Biology Laboratory (EMBL) for their support and Felix Weis for data collection and excellent technical support. Molecular graphics and analyses were performed with UCSF Chimera, developed by the Resource for Biocom-puting, Visualisation, and Informatics at the University of California, San Francisco, with support from NIH P41-GM103311. Molecular graphics and analyses performed with UCSF ChimeraX, developed by the Resource for Biocomputing, Visualisation, and Informatics at the University of California, San Fran-cisco, with support from National Institutes of Health R01-GM129325 and the Office of Cyber Infra-structure and Computational Biology, National Institute of Allergy and Infectious Diseases. This work was supported by The Israel Science Foundation (Grants No. 569/17 and 199/21), and by German-Israeli Foundation for Scientific Research and Development (GIF), Grant no. G-1483-207/2018. Y.M acknowledges the support by the National Science Foundation under Award No. 2034021. Publisher Copyright: {\textcopyright} Caspy et al.",
year = "2023",
doi = "10.7554/eLife.81150",
language = "English (US)",
volume = "12",
journal = "eLife",
issn = "2050-084X",
publisher = "eLife Sciences Publications",
}