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Green plant photosystem II (PSII) and light-harvesting complex II (LHCII) in the stacked grana regions of thylakoid membranes can self-organize into various PSII-LHCII supercomplexes with crystalline or fluid-like supramolecular structures to adjust themselves with external stimuli such as high/low light and temperatures, rendering tunable solar light absorption spectrum and photosynthesis efficiencies. However, the mechanisms controlling the PSII-LHCII supercomplex organizations remain elusive. In this work, we constructed a coarse-grained (CG) model of the thylakoid membrane including lipid molecules and a PSII-LHCII supercomplex considering association/dissociation of moderately bound-LHCIIs. The CG interaction between CG beads were constructed based on electron microscope (EM) experimental results, and we were able to simulate the PSII-LHCII supramolecular organization of a 500 × 500 nm(2) thylakoid membrane, which is compatible with experiments. Our CGMD simulations can successfully reproduce order structures of PSII-LHCII supercomplexes under various protein packing fractions, free-LHCII:PSII ratios, and temperatures, thereby providing insights into mechanisms leading to PSII-LHCII supercomplex organizations in photosynthetic membranes.
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http://dx.doi.org/10.1021/jp511277c | DOI Listing |
Plant J
August 2025
College of Life Science, Sichuan Agricultural University, Ya'an, 625014, China.
Chlorophyll (Chl) b deficiency leads to vulnerability to high light and oxidative stress in wheat plants, while the detailed mechanism by which Chl b is involved in photoprotection remains unclear in plants. In this study, the roles of thylakoid protein composition and complexes in photosynthetic electron transport, photoprotective responses, and energy dissipation were investigated in Chl b-deficient mutant lines (ANK-32A) and the wild type (WT) of wheat. Compared to the WT, ANK-32A showed higher non-photochemical quenching (NPQ), slower state transitions, and a significant decline in the amount of Lhca1-4, Lhcb1-3, and PSII-LHCII supercomplexes at the early growth stage.
View Article and Find Full Text PDFJ Plant Physiol
September 2025
The Franciszek Górski Institute of Plant Physiology, Polish Academy of Sciences, Niezapominajek 21, 30-239, Kraków, Poland.
Halophytes have been widely used to investigate plant salt tolerance, but the mechanisms regulating photosynthesis under salinity are still poorly understood. Here, the effect of 10-day NaCl irrigation on the phosphorylation status of photosystem II (PSII), a light-harvesting complex of PSII (LHCII) and the organization of protein complexes in thylakoids of the halophyte Mesembryanthemum crystallinum L. (common ice plant) was investigated.
View Article and Find Full Text PDFNat Plants
July 2025
Key Laboratory of Biomacromolecules (CAS), National Laboratory of Biomacromolecules, CAS Centre for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.
During oxygenic photosynthesis, photosystem II (PSII) uses light energy for oxidizing water and reducing plastoquinone. It is susceptible to photodamage, and the damaged PSII is repaired through a sophisticated biological process assisted by numerous auxiliary proteins. Here we report the cryogenic electron microscopy structures of four PSII-repair complexes from Chlamydomonas reinhardtii associated with the Thylakoid Enriched Fraction 30 (TEF30, an orthologue of plant MET1) protein-namely, a TEF30-PSII core monomer (TEF30-C), two types of TEF30-PSII core dimers (types I and II, TEF30-C-I and TEF30-C-II) and a TEF30-CS-type PSII-LHCII supercomplex (TEF30-CS; S, strongly associated light-harvesting complex II trimer).
View Article and Find Full Text PDFPhysiol Plant
June 2025
Molecular Plant Biology, Department of Life Technologies, University of Turku, Turku, Finland.
In nature, environmental conditions are constantly changing, requiring plants to have numerous regulatory mechanisms to keep light harvesting and metabolism in balance. Here, we show that high light (HL) induces a much stronger non-photochemical quenching (NPQ) when lettuce plants are exposed to 1500 μmol photons m s for 4 h at 13°C (low temperature, LT) compared to 23°C (growth temperature, GT). GT/HL treatment induced NPQ to relax during 1 h in darkness.
View Article and Find Full Text PDFPlant Physiol Biochem
July 2025
College of Life Science, Sichuan Agricultural University, 625014, Ya'an, China; State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu, 611130, China. Electronic address:
Hydrogen sulfide (HS) has been regarded as a small gasotransmitter associated with physiological and biochemical regulation in plant responses to environmental stresses. However, the regulatory mechanisms of HS in photosynthesis under adverse conditions remains poorly understood in plants. Here, the role of HS in the regulation of photosystem I (PSI) and photosystem II (PSII) was investigated in rice seedlings subjected to salt stress.
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