ID PSAB_THAPS Reviewed; 733 AA. AC A0T0M9; DT 06-FEB-2007, integrated into UniProtKB/Swiss-Prot. DT 09-JAN-2007, sequence version 1. DT 24-JAN-2024, entry version 73. DE RecName: Full=Photosystem I P700 chlorophyll a apoprotein A2 {ECO:0000255|HAMAP-Rule:MF_00482}; DE EC=1.97.1.12 {ECO:0000255|HAMAP-Rule:MF_00482}; DE AltName: Full=PSI-B {ECO:0000255|HAMAP-Rule:MF_00482}; DE AltName: Full=PsaB {ECO:0000255|HAMAP-Rule:MF_00482}; GN Name=psaB {ECO:0000255|HAMAP-Rule:MF_00482}; OS Thalassiosira pseudonana (Marine diatom) (Cyclotella nana). OG Plastid; Chloroplast. OC Eukaryota; Sar; Stramenopiles; Ochrophyta; Bacillariophyta; OC Coscinodiscophyceae; Thalassiosirophycidae; Thalassiosirales; OC Thalassiosiraceae; Thalassiosira. OX NCBI_TaxID=35128; RN [1] RP NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA]. RC STRAIN=CCMP1335 / NEPCC58 / CCAP 1085/12; RX PubMed=17252281; DOI=10.1007/s00438-006-0199-4; RA Oudot-Le Secq M.-P., Grimwood J., Shapiro H., Armbrust E.V., Bowler C., RA Green B.R.; RT "Chloroplast genomes of the diatoms Phaeodactylum tricornutum and RT Thalassiosira pseudonana: comparison with other plastid genomes of the red RT lineage."; RL Mol. Genet. Genomics 277:427-439(2007). CC -!- FUNCTION: PsaA and PsaB bind P700, the primary electron donor of CC photosystem I (PSI), as well as the electron acceptors A0, A1 and FX. CC PSI is a plastocyanin/cytochrome c6-ferredoxin oxidoreductase, CC converting photonic excitation into a charge separation, which CC transfers an electron from the donor P700 chlorophyll pair to the CC spectroscopically characterized acceptors A0, A1, FX, FA and FB in CC turn. Oxidized P700 is reduced on the lumenal side of the thylakoid CC membrane by plastocyanin or cytochrome c6. {ECO:0000255|HAMAP- CC Rule:MF_00482}. CC -!- CATALYTIC ACTIVITY: CC Reaction=hnu + oxidized [2Fe-2S]-[ferredoxin] + reduced [plastocyanin] CC = oxidized [plastocyanin] + reduced [2Fe-2S]-[ferredoxin]; CC Xref=Rhea:RHEA:30407, Rhea:RHEA-COMP:10000, Rhea:RHEA-COMP:10001, CC Rhea:RHEA-COMP:10039, Rhea:RHEA-COMP:10040, ChEBI:CHEBI:29036, CC ChEBI:CHEBI:30212, ChEBI:CHEBI:33737, ChEBI:CHEBI:33738, CC ChEBI:CHEBI:49552; EC=1.97.1.12; Evidence={ECO:0000255|HAMAP- CC Rule:MF_00482}; CC -!- COFACTOR: CC Note=P700 is a chlorophyll a/chlorophyll a' dimer, A0 is one or more CC chlorophyll a, A1 is one or both phylloquinones and FX is a shared 4Fe- CC 4S iron-sulfur center. {ECO:0000255|HAMAP-Rule:MF_00482}; CC -!- SUBUNIT: The PsaA/B heterodimer binds the P700 chlorophyll special pair CC and subsequent electron acceptors. PSI consists of a core antenna CC complex that captures photons, and an electron transfer chain that CC converts photonic excitation into a charge separation. The eukaryotic CC PSI reaction center is composed of at least 11 subunits. CC {ECO:0000255|HAMAP-Rule:MF_00482}. CC -!- SUBCELLULAR LOCATION: Plastid, chloroplast thylakoid membrane; Multi- CC pass membrane protein. CC -!- SIMILARITY: Belongs to the PsaA/PsaB family. {ECO:0000255|HAMAP- CC Rule:MF_00482}. CC --------------------------------------------------------------------------- CC Copyrighted by the UniProt Consortium, see https://www.uniprot.org/terms CC Distributed under the Creative Commons Attribution (CC BY 4.0) License CC --------------------------------------------------------------------------- DR EMBL; EF067921; ABK20714.1; -; Genomic_DNA. DR RefSeq; YP_874491.1; NC_008589.1. DR AlphaFoldDB; A0T0M9; -. DR SMR; A0T0M9; -. DR STRING; 35128.A0T0M9; -. DR PaxDb; 35128-Thapsdraft1611; -. DR GeneID; 4524814; -. DR eggNOG; ENOG502QRYE; Eukaryota. DR InParanoid; A0T0M9; -. DR OMA; EQWVADP; -. DR GO; GO:0009535; C:chloroplast thylakoid membrane; IEA:UniProtKB-SubCell. DR GO; GO:0009522; C:photosystem I; IEA:UniProtKB-KW. DR GO; GO:0051539; F:4 iron, 4 sulfur cluster binding; IEA:UniProtKB-KW. DR GO; GO:0016168; F:chlorophyll binding; IEA:UniProtKB-KW. DR GO; GO:0009055; F:electron transfer activity; IEA:UniProtKB-UniRule. DR GO; GO:0000287; F:magnesium ion binding; IEA:UniProtKB-UniRule. DR GO; GO:0015979; P:photosynthesis; IEA:UniProtKB-UniRule. DR Gene3D; 1.20.1130.10; Photosystem I PsaA/PsaB; 1. DR HAMAP; MF_00482; PSI_PsaB; 1. DR InterPro; IPR001280; PSI_PsaA/B. DR InterPro; IPR020586; PSI_PsaA/B_CS. DR InterPro; IPR036408; PSI_PsaA/B_sf. DR InterPro; IPR006244; PSI_PsaB. DR NCBIfam; TIGR01336; psaB; 1. DR PANTHER; PTHR30128; OUTER MEMBRANE PROTEIN, OMPA-RELATED; 1. DR PANTHER; PTHR30128:SF75; PHOTOSYSTEM I P700 CHLOROPHYLL A APOPROTEIN A2; 1. DR Pfam; PF00223; PsaA_PsaB; 1. DR PIRSF; PIRSF002905; PSI_A; 1. DR PRINTS; PR00257; PHOTSYSPSAAB. DR SUPFAM; SSF81558; Photosystem I subunits PsaA/PsaB; 1. DR PROSITE; PS00419; PHOTOSYSTEM_I_PSAAB; 1. PE 3: Inferred from homology; KW 4Fe-4S; Chlorophyll; Chloroplast; Chromophore; Electron transport; Iron; KW Iron-sulfur; Magnesium; Membrane; Metal-binding; Oxidoreductase; KW Photosynthesis; Photosystem I; Plastid; Thylakoid; Transmembrane; KW Transmembrane helix; Transport. FT CHAIN 1..733 FT /note="Photosystem I P700 chlorophyll a apoprotein A2" FT /id="PRO_0000277143" FT TRANSMEM 46..69 FT /note="Helical; Name=I" FT /evidence="ECO:0000255|HAMAP-Rule:MF_00482" FT TRANSMEM 134..157 FT /note="Helical; Name=II" FT /evidence="ECO:0000255|HAMAP-Rule:MF_00482" FT TRANSMEM 174..198 FT /note="Helical; Name=III" FT /evidence="ECO:0000255|HAMAP-Rule:MF_00482" FT TRANSMEM 272..290 FT /note="Helical; Name=IV" FT /evidence="ECO:0000255|HAMAP-Rule:MF_00482" FT TRANSMEM 329..352 FT /note="Helical; Name=V" FT /evidence="ECO:0000255|HAMAP-Rule:MF_00482" FT TRANSMEM 368..394 FT /note="Helical; Name=VI" FT /evidence="ECO:0000255|HAMAP-Rule:MF_00482" FT TRANSMEM 416..438 FT /note="Helical; Name=VII" FT /evidence="ECO:0000255|HAMAP-Rule:MF_00482" FT TRANSMEM 516..534 FT /note="Helical; Name=VIII" FT /evidence="ECO:0000255|HAMAP-Rule:MF_00482" FT TRANSMEM 574..595 FT /note="Helical; Name=IX" FT /evidence="ECO:0000255|HAMAP-Rule:MF_00482" FT TRANSMEM 642..664 FT /note="Helical; Name=X" FT /evidence="ECO:0000255|HAMAP-Rule:MF_00482" FT TRANSMEM 706..726 FT /note="Helical; Name=XI" FT /evidence="ECO:0000255|HAMAP-Rule:MF_00482" FT BINDING 558 FT /ligand="[4Fe-4S] cluster" FT /ligand_id="ChEBI:CHEBI:49883" FT /ligand_note="ligand shared between dimeric partners" FT /evidence="ECO:0000255|HAMAP-Rule:MF_00482" FT BINDING 567 FT /ligand="[4Fe-4S] cluster" FT /ligand_id="ChEBI:CHEBI:49883" FT /ligand_note="ligand shared between dimeric partners" FT /evidence="ECO:0000255|HAMAP-Rule:MF_00482" FT BINDING 653 FT /ligand="chlorophyll a" FT /ligand_id="ChEBI:CHEBI:58416" FT /ligand_label="B1" FT /ligand_part="Mg" FT /ligand_part_id="ChEBI:CHEBI:25107" FT /note="axial binding residue" FT /evidence="ECO:0000255|HAMAP-Rule:MF_00482" FT BINDING 661 FT /ligand="chlorophyll a" FT /ligand_id="ChEBI:CHEBI:58416" FT /ligand_label="B3" FT /ligand_part="Mg" FT /ligand_part_id="ChEBI:CHEBI:25107" FT /note="axial binding residue" FT /evidence="ECO:0000255|HAMAP-Rule:MF_00482" FT BINDING 669 FT /ligand="chlorophyll a" FT /ligand_id="ChEBI:CHEBI:58416" FT /ligand_label="B3" FT /evidence="ECO:0000255|HAMAP-Rule:MF_00482" FT BINDING 670 FT /ligand="phylloquinone" FT /ligand_id="ChEBI:CHEBI:18067" FT /ligand_label="B" FT /evidence="ECO:0000255|HAMAP-Rule:MF_00482" SQ SEQUENCE 733 AA; 82089 MW; F5C6FCBE674FB914 CRC64; MATKFPKFSQ ALAQDPATRR IWYGIATAHD LEAHDGMTEE NLYQKIFASH FGHLAIIFLW TSGNLFHVAW QGNFEKWVSN PLKTRPIAHS IWDPHFGESA LKAFSKGNTY PVNITFSGLY QWWYTIGFRT NQELYKGSIG LLLLASVLLI AGWLHLQPKF RPSLSWFKNN ESRLNHHLSG LLGFSSLAWT GHLVHVAIPA SRGVHVGWDN FLTTPPHPAG LTPFFTGNWT VYAENPDSAT HVFNTSEGSG TAILTFLGGF HPQTQSLWLS DMAHHHLAIA VVFIVAGHMY RTNFGIGHNM KEILDAHRPP GGRLGAGHVG LFETITNSLH MQLGLALACL GVATSLTAQH MYALTPYAYL SKDFTTEAAL YTHHQYIAGF LMVGAFAHGA IFFVRDYDPE LNKNNVLARM LEHKEAIISH LSWASLFLGF HTLGLYIHND TVVAFGQPEK QILFEPLFAE YIQAASGKAV YQFNVLLASS TSPATAAGNQ VWLPGWLEAI NNPKTDLFLK IGPGDFLVHH AIALGLHVTA LILVKGALDA RGSKLMPDKK DFGYSFPCDG PGRGGTCDIS AWDAFYLAMF WMLNTIGWVT FYWHWKHMTI WGGNPGQFDE SSNYIMGWLR DYLWLNSSPL INGYNPFGMN NLSVWSWMFL FGHLIWATGF MFLISWRGYW QELIETLVWA HERTPLANLI RWRDKPVALS IVQARLVGLV HFSVGYILTY AAFVIASTSG KFA //