PSAB_MASLA
ID PSAB_MASLA Reviewed; 743 AA.
AC O52475;
DT 15-DEC-1998, integrated into UniProtKB/Swiss-Prot.
DT 23-JAN-2007, sequence version 3.
DT 03-AUG-2022, entry version 102.
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=PsaB {ECO:0000255|HAMAP-Rule:MF_00482};
GN Name=psaB {ECO:0000255|HAMAP-Rule:MF_00482};
OS Mastigocladus laminosus (Fischerella sp.).
OC Bacteria; Cyanobacteria; Nostocales; Hapalosiphonaceae; Mastigocladus.
OX NCBI_TaxID=83541;
RN [1]
RP NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RC STRAIN=PCC 7605;
RA Sun J., He Z.-Y., Nechushtai R., Chitnis P.R.;
RT "Molecular cloning of the psaA and psaB genes for the core proteins of
RT photosystem I from the thermophilic cyanobacterium Mastigocladus
RT laminosus.";
RL (er) Plant Gene Register PGR98-041(1998).
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=PSI electron transfer chain: 5 chlorophyll a, 1 chlorophyll a', 2
CC phylloquinones and 3 4Fe-4S clusters. PSI core antenna: 90 chlorophyll
CC a, 22 carotenoids, 3 phospholipids and 1 galactolipid. P700 is a
CC chlorophyll a/chlorophyll a' dimer, A0 is one or more chlorophyll a, A1
CC is one or both phylloquinones and FX is a shared 4Fe-4S iron-sulfur
CC 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
CC cyanobacterial PSI reaction center is composed of one copy each of
CC PsaA,B,C,D,E,F,I,J,K,L,M and X, and forms trimeric complexes.
CC {ECO:0000255|HAMAP-Rule:MF_00482}.
CC -!- SUBCELLULAR LOCATION: Cellular thylakoid membrane {ECO:0000255|HAMAP-
CC Rule:MF_00482}; Multi-pass membrane protein {ECO:0000255|HAMAP-
CC Rule:MF_00482}.
CC -!- SIMILARITY: Belongs to the PsaA/PsaB family. {ECO:0000255|HAMAP-
CC Rule:MF_00482}.
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DR EMBL; AF038558; AAC12867.1; -; Genomic_DNA.
DR AlphaFoldDB; O52475; -.
DR SMR; O52475; -.
DR GO; GO:0016021; C:integral component of membrane; IEA:UniProtKB-KW.
DR GO; GO:0009522; C:photosystem I; IEA:UniProtKB-KW.
DR GO; GO:0031676; C:plasma membrane-derived thylakoid membrane; IEA:UniProtKB-SubCell.
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; -; 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 Pfam; PF00223; PsaA_PsaB; 1.
DR PIRSF; PIRSF002905; PSI_A; 1.
DR PRINTS; PR00257; PHOTSYSPSAAB.
DR SUPFAM; SSF81558; SSF81558; 1.
DR TIGRFAMs; TIGR01336; psaB; 1.
DR PROSITE; PS00419; PHOTOSYSTEM_I_PSAAB; 1.
PE 3: Inferred from homology;
KW 4Fe-4S; Chlorophyll; Chromophore; Electron transport; Iron; Iron-sulfur;
KW Magnesium; Membrane; Metal-binding; Oxidoreductase; Photosynthesis;
KW Photosystem I; Thylakoid; Transmembrane; Transmembrane helix; Transport.
FT INIT_MET 1
FT /note="Removed"
FT /evidence="ECO:0000250"
FT CHAIN 2..743
FT /note="Photosystem I P700 chlorophyll a apoprotein A2"
FT /id="PRO_0000088645"
FT TRANSMEM 46..69
FT /note="Helical; Name=I"
FT /evidence="ECO:0000255|HAMAP-Rule:MF_00482"
FT TRANSMEM 135..158
FT /note="Helical; Name=II"
FT /evidence="ECO:0000255|HAMAP-Rule:MF_00482"
FT TRANSMEM 175..199
FT /note="Helical; Name=III"
FT /evidence="ECO:0000255|HAMAP-Rule:MF_00482"
FT TRANSMEM 273..291
FT /note="Helical; Name=IV"
FT /evidence="ECO:0000255|HAMAP-Rule:MF_00482"
FT TRANSMEM 336..359
FT /note="Helical; Name=V"
FT /evidence="ECO:0000255|HAMAP-Rule:MF_00482"
FT TRANSMEM 375..401
FT /note="Helical; Name=VI"
FT /evidence="ECO:0000255|HAMAP-Rule:MF_00482"
FT TRANSMEM 423..445
FT /note="Helical; Name=VII"
FT /evidence="ECO:0000255|HAMAP-Rule:MF_00482"
FT TRANSMEM 526..544
FT /note="Helical; Name=VIII"
FT /evidence="ECO:0000255|HAMAP-Rule:MF_00482"
FT TRANSMEM 584..605
FT /note="Helical; Name=IX"
FT /evidence="ECO:0000255|HAMAP-Rule:MF_00482"
FT TRANSMEM 652..674
FT /note="Helical; Name=X"
FT /evidence="ECO:0000255|HAMAP-Rule:MF_00482"
FT TRANSMEM 716..736
FT /note="Helical; Name=XI"
FT /evidence="ECO:0000255|HAMAP-Rule:MF_00482"
FT BINDING 568
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 577
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 663
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 671
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 679
FT /ligand="chlorophyll a"
FT /ligand_id="ChEBI:CHEBI:58416"
FT /ligand_label="B3"
FT /evidence="ECO:0000255|HAMAP-Rule:MF_00482"
FT BINDING 680
FT /ligand="phylloquinone"
FT /ligand_id="ChEBI:CHEBI:18067"
FT /ligand_label="B"
FT /evidence="ECO:0000255|HAMAP-Rule:MF_00482"
SQ SEQUENCE 743 AA; 83513 MW; C7338B8883D21385 CRC64;
MATKFPKFSQ DLAQDPTTRR IWYAMATGND FESHDGMTEE NLYQKIFATH FGHVAIIFLW
ASSLLFHVAW QGNFEQWIKD PIHIRPIAHA IWDPQFGKPA IEAFTQGGAN YPVNISYSGI
YHWWYTIGMR TNNDLYMGAV FLLILASVFL FAGWLHLQPK FRPSLSWFKS AEPRLNHHLA
GLFGVSSLAW AGHLIHVAIP ESRGQHVGWN NFLSTLPHPA GLQPFFTGNW GVYASDPDTA
NHVFGTSQGA GTAILTFLGG FHPQTESLWL TDMAHHHLAI AVIFIIAGHM YRTNFGIGHS
IKEMLNSKAG LVPGTNSEGQ FNLPHQGLYD TYNNSLHFQL GIHLAALGTI TSLVAQHMYA
MPPYAFIAKD YTTQAALYTH HQYIAIFLML GAFAHGAIFW VRDYDPEQNK GNVLDRVLKH
KEAIISHLSW VSLFLGFHTL GLYVHNDVVV AFGTPEKQIL IEPVFAQFIQ ASHGKVLYGL
NVLLSNPDSV AYTAYPNYGN VWLQGWLDAI NSGTNSLFLT IGPGDFLVHH AFALALHTTV
LILVKGALDA RGSKLMPDKK DFGYAFPCDG PGRGGTCDIS AWDAFYLATF WALNTVGWVT
FYWHWKHLGI WQGNVAQFNE SSTYLMGWFR DYLWANSAQL INGYNPYGMN NLSVWAWMFL
FGHLVWATGF MFLISWRGYW QELIETLVWA HERTPLANLV RWKDKPVALS IVQARLVGLT
HFTVGYVLTY AAFLIASTAG KFG
