5zf0
From Proteopedia
X-ray Structure of the Electron Transfer Complex between Ferredoxin and Photosystem I
Structural highlights
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Function[PSAF_THEEB] Probably participates in efficiency of electron transfer from plastocyanin to P700 (or cytochrome c553 in algae and cyanobacteria). This plastocyanin-docking protein contributes to the specific association of plastocyanin to PSI (By similarity). [PSAC_THEEB] Apoprotein for the two 4Fe-4S centers FA and FB of photosystem I (PSI); essential for photochemical activity. FB is the terminal electron acceptor of PSI, donating electrons to ferredoxin. The C-terminus interacts with PsaA/B/D and helps assemble the protein into the PSI complex. Required for binding of PsaD and PsaE to PSI. 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. [PSAI_THEEB] May help in the organization of the PsaL subunit. [PSAB_THEEB] 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. [PSAJ_THEEB] May help in the organization of the PsaE and PsaF subunits. [PSAA_THEEB] 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. [PSAD_THEEB] PsaD can form complexes with ferredoxin and ferredoxin-oxidoreductase in photosystem I (PS I) reaction center. [FER_THEEB] Ferredoxins are iron-sulfur proteins that transfer electrons in a wide variety of metabolic reactions. [PSAE_THEEB] Stabilizes the interaction between PsaC and the PSI core, assists the docking of the ferredoxin to PSI and interacts with ferredoxin-NADP oxidoreductase. Publication Abstract from PubMedPhotosystem I (PSI), a large protein complex located in the thylakoid membrane, mediates the final step in light-driven electron transfer to the stromal electron carrier protein ferredoxin (Fd). Here, we report the first structural description of the PSI-Fd complex from Thermosynechococcus elongatus. The trimeric PSI complex binds three Fds in a non-equivalent manner. While each is recognized by a PSI protomer in a similar orientation, the distances between Fds and the PSI redox centres differ. Fd binding thus entails loss of the exact three-fold symmetry of the PSI's soluble subunits, inducing structural perturbations which are transferred to the lumen through PsaF. Affinity chromatography and nuclear magnetic resonance analyses of PSI-Fd complexes support the existence of two different Fd-binding states, with one Fd being more tightly bound than the others. We propose a dynamic structural basis for productive complex formation, which supports fast electron transfer between PSI and Fd. X-ray structure of an asymmetrical trimeric ferredoxin-photosystem I complex.,Kubota-Kawai H, Mutoh R, Shinmura K, Setif P, Nowaczyk MM, Rogner M, Ikegami T, Tanaka H, Kurisu G Nat Plants. 2018 Apr;4(4):218-224. doi: 10.1038/s41477-018-0130-0. Epub 2018 Apr , 2. PMID:29610537[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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