---
DOAJ_listed: '1'
OA_place: publisher
OA_type: gold
_id: '22750'
abstract:
- lang: eng
  text: 'Robust oxygenic photosynthesis requires the efficient assembly and repair
    of the multi-subunit oxygen-evolving photosystem II (PSII) complex. Previous cryogenic
    electron microscopy (cryo-EM) structures of PSII assembly/disassembly intermediates
    have relied on the analysis of deletion mutants or removal of PSII subunits in
    vitro. Here we report the cryo-EM structures of naturally occurring dimeric PSII
    intermediates from the cyanobacterium Thermosynechococcus vestitus at a resolution
    of about 2.2 Å. These intermediates contain inactive dimers lacking the oxygen-evolving
    complex (OEC) and semi-active dimers with the OEC present in one of the two monomers.
    Our structural data provide a mechanism for how assembly and disassembly of the
    Mn4CaO5 cluster is coordinated with the binding and release of the extrinsic proteins:
    restructuring of the C-terminal tail of D1 subunit during assembly or disassembly
    of the Mn cluster triggers conformational changes in D2, CP47 and CP43 to drive
    the binding/release of the extrinsic proteins. A combination of structural and
    mass spectrometry data also suggests that the inactive PSII complexes may include
    damaged complexes containing oxidized D1-His332, a monodentate ligand to one of
    the Mn ions of the OEC.'
acknowledged_ssus:
- _id: EM-Fac
- _id: LifeSc
- _id: ScienComp
acknowledgement: 'P.J.N. is grateful for the support from the Imperial College Electron
  Microscopy Center. L.A.S. acknowledges the support from the Scientific Service Units
  (SSU) of IST Austria: the Electron Microscopy Facility (EMF), the Life Science Facility
  (LSF) and the IST high-performance computing cluster. P.J.N. is grateful for the
  support of the Biotechnology & Biological Sciences Research Council (awards BB/I00937X/1,
  BB/L003260/1 and BB/P00931X/1). L.A.S. is grateful to IST Austria for providing
  the funding.'
article_number: '8433'
article_processing_charge: Yes
article_type: original
author:
- first_name: Ziyu
  full_name: Zhao, Ziyu
  id: a63fe682-9f3a-11ee-bf8c-cfdf919b9850
  last_name: Zhao
- first_name: Irene
  full_name: Vercellino, Irene
  id: 3ED6AF16-F248-11E8-B48F-1D18A9856A87
  last_name: Vercellino
  orcid: 0000-0001-5618-3449
- first_name: Julian P.
  full_name: Whitelegge, Julian P.
  last_name: Whitelegge
- first_name: Karim
  full_name: Maghlaoui, Karim
  last_name: Maghlaoui
- first_name: Wojciech
  full_name: Białek, Wojciech
  last_name: Białek
- first_name: Peter J.
  full_name: Nixon, Peter J.
  last_name: Nixon
- first_name: Leonid A
  full_name: Sazanov, Leonid A
  id: 338D39FE-F248-11E8-B48F-1D18A9856A87
  last_name: Sazanov
  orcid: 0000-0002-0977-7989
citation:
  ama: Zhao Z, Vercellino I, Whitelegge JP, et al. Cryo-EM structures of naturally
    occurring dimeric photosystem II complexes lacking the Mn4CaO5 cluster. <i>Nature
    Communications</i>. 2026;17. doi:<a href="https://doi.org/10.1038/s41467-026-75324-x">10.1038/s41467-026-75324-x</a>
  apa: Zhao, Z., Vercellino, I., Whitelegge, J. P., Maghlaoui, K., Białek, W., Nixon,
    P. J., &#38; Sazanov, L. A. (2026). Cryo-EM structures of naturally occurring
    dimeric photosystem II complexes lacking the Mn4CaO5 cluster. <i>Nature Communications</i>.
    Springer Nature. <a href="https://doi.org/10.1038/s41467-026-75324-x">https://doi.org/10.1038/s41467-026-75324-x</a>
  chicago: Zhao, Ziyu, Irene Vercellino, Julian P. Whitelegge, Karim Maghlaoui, Wojciech
    Białek, Peter J. Nixon, and Leonid A Sazanov. “Cryo-EM Structures of Naturally
    Occurring Dimeric Photosystem II Complexes Lacking the Mn4CaO5 Cluster.” <i>Nature
    Communications</i>. Springer Nature, 2026. <a href="https://doi.org/10.1038/s41467-026-75324-x">https://doi.org/10.1038/s41467-026-75324-x</a>.
  ieee: Z. Zhao <i>et al.</i>, “Cryo-EM structures of naturally occurring dimeric
    photosystem II complexes lacking the Mn4CaO5 cluster,” <i>Nature Communications</i>,
    vol. 17. Springer Nature, 2026.
  ista: Zhao Z, Vercellino I, Whitelegge JP, Maghlaoui K, Białek W, Nixon PJ, Sazanov
    LA. 2026. Cryo-EM structures of naturally occurring dimeric photosystem II complexes
    lacking the Mn4CaO5 cluster. Nature Communications. 17, 8433.
  mla: Zhao, Ziyu, et al. “Cryo-EM Structures of Naturally Occurring Dimeric Photosystem
    II Complexes Lacking the Mn4CaO5 Cluster.” <i>Nature Communications</i>, vol.
    17, 8433, Springer Nature, 2026, doi:<a href="https://doi.org/10.1038/s41467-026-75324-x">10.1038/s41467-026-75324-x</a>.
  short: Z. Zhao, I. Vercellino, J.P. Whitelegge, K. Maghlaoui, W. Białek, P.J. Nixon,
    L.A. Sazanov, Nature Communications 17 (2026).
corr_author: '1'
das_tickbox: '1'
dataavailabilitystatement: The cryo-EM maps are deposited in the Electron Microscopy
  Data Bank under accession number EMD- 51100 (inactive dimer), EMD- 51102 (active
  dimer) and EMD-51101 (semi-active dimer). The models are deposited in the Protein
  Data Bank under accession numbers 9G6F (inactive dimer), 9G6H (active dimer) and
  9G6G (semi-active dimer). Mass spectrometry data was uploaded to MassIVE with accession
  code MSV000101057. Source data are provided with this paper.
date_created: 2026-08-23T22:01:46Z
date_published: 2026-08-17T00:00:00Z
date_updated: 2026-09-07T13:17:53Z
day: '17'
ddc:
- '570'
department:
- _id: LeSa
doi: 10.1038/s41467-026-75324-x
external_id:
  pmid:
  - '42420307'
file:
- access_level: open_access
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  creator: dernst
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  date_updated: 2026-09-07T13:13:03Z
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fulldoi: https://doi.org/10.1038/s41467-026-75324-x
has_accepted_license: '1'
intvolume: '        17'
language:
- iso: eng
month: '08'
oa: 1
oa_version: Published Version
pmid: 1
publication: Nature Communications
publication_identifier:
  eissn:
  - 2041-1723
publication_status: published
publisher: Springer Nature
quality_controlled: '1'
researchdata_availability: yes
scopus_import: '1'
status: public
supplementarymaterial: yes
title: Cryo-EM structures of naturally occurring dimeric photosystem II complexes
  lacking the Mn4CaO5 cluster
tmp:
  image: /images/cc_by_nc_nd.png
  legal_code_url: https://creativecommons.org/licenses/by-nc-nd/4.0/legalcode
  name: Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International
    (CC BY-NC-ND 4.0)
  short: CC BY-NC-ND (4.0)
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 17
year: '2026'
...