6kmx

Structure of PSI from H. hongdechloris grown under far-red light condition

Loading... Status: waiting for Mol* initialization Structural highlights 6kmx is a 27 chain structure with sequence from Halomicronema hongdechloris C2206. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: Electron Microscopy, Resolution 2.41Å Ligands: BCR, CA, CLA, F6C, LHG, LMG, LMT, PQN Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function A0A1Z3HIN6_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 Chlorophylls (Chl) play pivotal roles in energy capture, transfer and charge separation in photosynthesis. Among Chls functioning in oxygenic photosynthesis, Chl f is the most red-shifted type first found in a cyanobacterium Halomicronema hongdechloris. The location and function of Chl f in photosystems are not clear. Here we analyzed the high-resolution structures of photosystem I (PSI) core from H. hongdechloris grown under white or far-red light by cryo-electron microscopy. The structure showed that, far-red PSI binds 83 Chl a and 7 Chl f, and Chl f are associated at the periphery of PSI but not in the electron transfer chain. The appearance of Chl f is well correlated with the expression of PSI genes induced under far-red light. These results indicate that Chl f functions to harvest the far-red light and enhance uphill energy transfer, and changes in the gene sequences are essential for the binding of Chl f. Structural basis for the adaptation and function of chlorophyll f in photosystem I.,Kato K, Shinoda T, Nagao R, Akimoto S, Suzuki T, Dohmae N, Chen M, Allakhverdiev SI, Shen JR, Akita F, Miyazaki N, Tomo T Nat Commun. 2020 Jan 13;11(1):238. doi: 10.1038/s41467-019-13898-5. PMID:31932639 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Photosystem I 3D structures

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