biostudies-literatureUnknown10(50)Shan JPhotosystem II (PSII) splits water in oxygenic photosynthesis on Earth. The structure and function of the C₄S₄M₂-type PSII-LHCII (light-harvesting complex II) megacomplexes from the wild-type and PsbR-deletion mutant plants are studied through electron microscopy (EM), structural mass spectrometry, and ultrafast fluorescence spectroscopy [time-resolved fluorescence (TRF)]. The cryo-EM structure of a type I C₄S₄M₂ megacomplex demonstrates that the three domains of PsbR bind to the stromal side of D1, D2, and CP43; associate with the single transmembrane helix of the redox active Cyt <i>b</i>₅₅₉; and stabilize the luminal extrinsic PsbP, respectively. This megacomplex, with PsbR and PsbY centered around the narrow iScience advanceseadq9967https://www.ebi.ac.uk/biostudies/studies/S-EPMC11640958biostudies-literatureArchitecture and functional regulation of a plant PSII-LHCII megacomplex.PMC11640958Liu HNiedzwiedzki DMLiu ZShan JTomar RSfalseArchitecture and functional regulation of a plant PSII-LHCII megacomplex.Photosystem II (PSII) splits water in oxygenic photosynthesis on Earth. The structure and function of the C₄S₄M₂-type PSII-LHCII (light-harvesting complex II) megacomplexes from the wild-type and PsbR-deletion mutant plants are studied through electron microscopy (EM), structural mass spectrometry, and ultrafast fluorescence spectroscopy [time-resolved fluorescence (TRF)]. The cryo-EM structure of a type I C₄S₄M₂ megacomplex demonstrates that the three domains of PsbR bind to the stromal side of D1, D2, and CP43; associate with the single transmembrane helix of the redox active Cyt <i>b</i>₅₅₉; and stabilize the luminal extrinsic PsbP, respectively. This megacomplex, with PsbR and PsbY centered around the narrow i2024-01-01T00:00:00Z2024 Dec2026-06-03T03:08:21.938Z2025-04-04T02:15:48.326ZS-EPMC116409583967147310.1126/sciadv.adq9967