2o01
From Proteopedia
The Structure of a plant photosystem I supercomplex at 3.4 Angstrom resolution
Structural highlights
Function[PSAF_SPIOL] 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. [PSAC_PEA] 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-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 (By similarity).[HAMAP-Rule:MF_01303] [PSAI_PEA] May help in the organization of the PsaL subunit. [PSAB_PEA] 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 (By similarity). [CB24_PEA] The light-harvesting complex (LHC) functions as a light receptor, it captures and delivers excitation energy to photosystems with which it is closely associated.[1] May channel protons produced in the catalytic Mn center of water oxidation into the thylakoid lumen.[2] [CAB6_ARATH] The light-harvesting complex (LHC) functions as a light receptor, it captures and delivers excitation energy to photosystems with which it is closely associated. [PSAH_SPIOL] Possible role could be the docking of the LHC I antenna complex to the core complex. [PSAD_SPIOL] PsaD can form complexes with ferredoxin and ferredoxin-oxidoreductase in photosystem I (PS I) reaction center. PSAD may encode the ferredoxin-docking protein. [PSAA_PEA] 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. [PSAJ_SPIOL] May help in the organization of the PsaE and PsaF subunits. [PSAE1_ARATH] Stabilizes the interaction between PsaC and the PSI core, assists the docking of the ferredoxin to PSI and interacts with ferredoxin-NADP oxidoreductase (By similarity). Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedAll higher organisms on Earth receive energy directly or indirectly from oxygenic photosynthesis performed by plants, green algae and cyanobacteria. Photosystem I (PSI) is a supercomplex of a reaction centre and light-harvesting complexes. It generates the most negative redox potential in nature, and thus largely determines the global amount of enthalpy in living systems. We report the structure of plant PSI at 3.4 A resolution, revealing 17 protein subunits. PsaN was identified in the luminal side of the supercomplex, and most of the amino acids in the reaction centre were traced. The crystal structure of PSI provides a picture at near atomic detail of 11 out of 12 protein subunits of the reaction centre. At this level, 168 chlorophylls (65 assigned with orientations for Q(x) and Q(y) transition dipole moments), 2 phylloquinones, 3 Fe(4)S(4) clusters and 5 carotenoids are described. This structural information extends the understanding of the most efficient nano-photochemical machine in nature. The structure of a plant photosystem I supercomplex at 3.4 A resolution.,Amunts A, Drory O, Nelson N Nature. 2007 May 3;447(7140):58-63. PMID:17476261[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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