Q9R6T9 A5GIQ3 PSAB_SYNPW Photosystem I P700 chlorophyll a apoprotein A2 1.97.1.12 PsaB psaB SynWH7803_0392 Synechococcus sp. (strain WH7803) Bacteria Bacillati Cyanobacteriota Cyanophyceae Synechococcales Synechococcaceae Synechococcus NUCLEOTIDE SEQUENCE [GENOMIC DNA] NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA] WH7803 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. reduced [plastocyanin] + hnu + oxidized [2Fe-2S]-[ferredoxin] = oxidized [plastocyanin] + reduced [2Fe-2S]-[ferredoxin] PSI electron transfer chain: 5 chlorophyll a, 1 chlorophyll a', 2 phylloquinones and 3 4Fe-4S clusters. PSI core antenna: 90 chlorophyll a, 22 carotenoids, 3 phospholipids and 1 galactolipid. P700 is a chlorophyll a/chlorophyll a' dimer, A0 is one or more chlorophyll a, A1 is one or both phylloquinones and FX is a shared 4Fe-4S iron-sulfur center. The PsaA/B heterodimer binds the P700 chlorophyll special pair and subsequent electron acceptors. PSI consists of a core antenna complex that captures photons, and an electron transfer chain that converts photonic excitation into a charge separation. The cyanobacterial PSI reaction center is composed of one copy each of PsaA,B,C,D,E,F,I,J,K,L,M and X, and forms trimeric complexes. Cellular thylakoid membrane Multi-pass membrane protein Belongs to the PsaA/PsaB family. 4Fe-4S Chlorophyll Chromophore Electron transport Iron Iron-sulfur Magnesium Membrane Metal-binding Oxidoreductase Photosynthesis Photosystem I Reference proteome Thylakoid Transmembrane Transmembrane helix Transport [4Fe-4S] cluster ligand shared between dimeric partners [4Fe-4S] cluster ligand shared between dimeric partners chlorophyll a B1 Mg chlorophyll a B3 Mg chlorophyll a B3 phylloquinone B MATKFPSFSQGLAQDPTTRRIWYGIATAHDFESHDGMTEEKLYQKLFSTHFGHLAIIGLWVSGNLFHIAWQGNFEQWVADPLHVRPIAHAIWDPHFGQGAIDAFTQAGASSPVNIAYSGLYHWFYTIGMTTNAELYQGSIFMMILSAWALFAGWLHLQPKFRPSLAWFKNAESRLNHHLAVLFGFSSIAWTGHLVHVAIPESRGQHVGWDNFLNVMPHPAGLGPFFTGNWGVYAQNPDTMGQVFGSAEGSGTAILTFLGGFHPQTEALWLTDIAHHHLAIGVIFVIAGHMYRTNFGIGHSIREILEAHNPPQGTPGDLGAGHKGLYDTINNSLHFQLGLALASLGVVTSLVAQHMYAMPSYAFIAKDYTTQAALYTHHQYIAIFLMCGAFAHGAIFFIRDYDPEANKDNVLARMLEHKEAIISHLSWVSLFLGFHTLGLYVHNDVVVAFGTPEKQILVEPVFAQFVQAASGKAIYGFDVLLANTGGVAANANAAYMGGWMDAINGVRGSNDLFLPIGPGDFLVHHAIALGLHTTTLILVKGALDARGSKLMPDKKDFGYSFPCDGPGRGGTCDISAWDAFYLAVFWALNTVGWVTFYWHWKHLAIWQGNVAQFNESSTYLMGWFRDYLWLNSSQLINGYNPFGSNNLAVWAWMFLFGHLVWATGFMFLISWRGYWQELIETIVWAHQRTPLANLVGWRDKPVALSIVQARVVGLAHFTIGYILTYAAFLIASTSGKFG Copyrighted by the UniProt Consortium, see https://www.uniprot.org/terms Distributed under the Creative Commons Attribution (CC BY 4.0) License