7ksq

The Structure of the moss PSI-LHCI reveals the evolution of the LHCI antenna

spinqualitylabelsall models 7ksq, resolution 2.80Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 7ksq is a 10 chain structure with sequence from Physcomitrium patens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: Electron Microscopy, Resolution 2.8Å Ligands: BCR, CLA, DGD, LHG, LMG, LMT, LUT, PQN Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function PSAA_PHYPA PsaA and PsaB bind P700, the primary electron donor of photosystem I (PSI), as well as the electron acceptors A0, A1 and FX. PSI is a plastocyanin-ferredoxin oxidoreductase, converting photonic excitation into a charge separation, which transfers an electron from the donor P700 chlorophyll pair to the spectroscopically characterized acceptors A0, A1, FX, FA and FB in turn. Oxidized P700 is reduced on the lumenal side of the thylakoid membrane by plastocyanin. Publication Abstract from PubMed The moss Physcomitrium patens diverged from green algae shortly after the colonization of land by ancient plants. This colonization posed new environmental challenges, which drove evolutionary processes. The photosynthetic machinery of modern flowering plants is adapted to the high light conditions on land. Red-shifted Lhca4 antennae are present in the photosystem I light-harvesting complex of many green-lineage plants but absent in P. patens. The cryo-EM structure of the P. patens photosystem I light-harvesting complex I supercomplex (PSI-LHCI) at 2.8 A reveals that Lhca4 is replaced by a unique Lhca2 paralogue in moss. This PSI-LHCI supercomplex also retains the PsaM subunit, present in Cyanobacteria and several algal species but lost in vascular plants, and the PsaO subunit responsible for binding light-harvesting complex II. The blue-shifted Lhca2 paralogue and chlorophyll b enrichment relative to flowering plants make the P. patens PSI-LHCI spectroscopically unique among other green-lineage supercomplexes. Overall, the structure represents an evolutionary intermediate PSI with the crescent-shaped LHCI common in vascular plants, and contains a unique Lhca2 paralogue that facilitates the moss's adaptation to low-light niches. The structure of the Physcomitrium patens photosystem I reveals a unique Lhca2 paralogue replacing Lhca4.,Gorski C, Riddle R, Toporik H, Da Z, Dobson Z, Williams D, Mazor Y Nat Plants. 2022 Mar;8(3):307-316. doi: 10.1038/s41477-022-01099-w. Epub 2022 Feb, 21. PMID:35190662 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Photosystem I 3D structures

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