7qco | pdb_00007qco

The structure of Photosystem I tetramer from Chroococcidiopsis TS-821, a thermophilic, unicellular, non-heterocyst-forming cyanobacterium

spinqualitylabelsall models 7qco, resolution 3.70Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 7qco is a 40 chain structure with sequence from Chroococcidiopsis sp. TS-821. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: Electron Microscopy, Resolution 3.7Å Ligands: BCR, CLA, LHG, PQN Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function A0A2S6VGM5_9CYAN 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/cytochrome c6-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 or cytochrome c6.[HAMAP-Rule:MF_00458] PsaA and psaB bind P700, the primary electron donor of photosystem I (PSI), as well as the electron acceptors A0, A1 and FX.[RuleBase:RU003775] Publication Abstract from PubMed Photosystem I (PSI) is one of two photosystems involved in oxygenic photosynthesis. PSI of cyanobacteria exists in monomeric, trimeric, and tetrameric forms, in contrast to the strictly monomeric form of PSI in plants and algae. The tetrameric organization raises questions about its structural, physiological, and evolutionary significance. Here we report the approximately 3.72 A resolution cryo-electron microscopy structure of tetrameric PSI from the thermophilic, unicellular cyanobacterium Chroococcidiopsis sp. TS-821. The structure resolves 44 subunits and 448 cofactor molecules. We conclude that the tetramer is arranged via two different interfaces resulting from a dimer-of-dimers organization. The localization of chlorophyll molecules permits an excitation energy pathway within and between adjacent monomers. Bioinformatics analysis reveals conserved regions in the PsaL subunit that correlate with the oligomeric state. Tetrameric PSI may function as a key evolutionary step between the trimeric and monomeric forms of PSI organization in photosynthetic organisms. Cryo-EM structure of a tetrameric photosystem I from Chroococcidiopsis TS-821, a thermophilic, unicellular, non-heterocyst-forming cyanobacterium.,Semchonok DA, Mondal J, Cooper CJ, Schlum K, Li M, Amin M, Sorzano COS, Ramirez-Aportela E, Kastritis PL, Boekema EJ, Guskov A, Bruce BD Plant Commun. 2021 Oct 13;3(1):100248. doi: 10.1016/j.xplc.2021.100248. , eCollection 2022 Jan 10. PMID:35059628 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Photosystem I 3D structures

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