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HAMAP rule MF_00482

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General rule information [?]

Accession MF_00482
Dates 1-JUN-2001 (Created)
3-SEP-2024 (Last updated, Version 71)
Name PSI_PsaB
Scope(s) Bacteria
Cyanobacteriota
Plastid
Template(s) P09144 (PSAB_CHLRE); P06512 (PSAB_SPIOL); P0A407 (PSAB_THEVB); P0A408 (PSAB_SYNEL); P29255 (PSAB_SYNY3); [ Recover all ]
Triggered by HAMAP; MF_00482 (Get profile general information and statistics)

Propagated annotation [?]

Identifier, protein and gene names [?]

Identifier PSAB
case not <OG:Chloroplast>
Protein name RecName: Full=Photosystem I P700 chlorophyll a apoprotein A2;
                 EC=1.97.1.12;
AltName: Full=PsaB;
else case <OG:Chloroplast>
Protein name RecName: Full=Photosystem I P700 chlorophyll a apoprotein A2;
                 EC=1.97.1.12;
AltName: Full=PSI-B;
AltName: Full=PsaB;
end case
Gene name Name=psaB;

Comments [?]

case <OC:Cyanobacteriota> or <OG:Chloroplast> and not <OC:Streptophyta>
FUNCTIONPsaA 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.
else case <OG:Chloroplast> and <OC:Streptophyta>
FUNCTIONPsaA 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.
end case
CATALYTIC ACTIVITY Reaction=reduced [plastocyanin] + hnu + oxidized [2Fe-2S]-[ferredoxin] = oxidized [plastocyanin] + reduced [2Fe-2S]-[ferredoxin]; Xref=Rhea:RHEA:30407, Rhea:RHEA-COMP:10000, Rhea:RHEA-COMP:10001, Rhea:RHEA-COMP:10039, Rhea:RHEA-COMP:10040, ChEBI:CHEBI:29036, ChEBI:CHEBI:30212, ChEBI:CHEBI:33737, ChEBI:CHEBI:33738, ChEBI:CHEBI:49552; EC=1.97.1.12;
case <OC:Cyanobacteriota> and not <OC:Prochlorococcus>
COFACTOR Note=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.;
SUBUNITThe 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.
else case <OC:Prochlorococcus>
COFACTOR Note=PSI electron transfer chain: 5 divinyl chlorophyll a, 1 divinyl chlorophyll a', 2 phylloquinones and 3 4Fe-4S clusters. PSI core antenna: 90 divinyl chlorophyll a, 22 carotenoids, 3 phospholipids and 1 galactolipid. P700 is a divinyl chlorophyll a/divinyl chlorophyll a' dimer, A0 is one or more divinyl chlorophyll a, A1 is one or both phylloquinones and FX is a shared 4Fe-4S iron-sulfur center.;
SUBUNITThe PsaA/B heterodimer binds the P700 divinyl 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.
else case <OG:Chloroplast>
COFACTOR Note=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.;
SUBUNITThe 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 eukaryotic PSI reaction center is composed of at least 11 subunits.
end case
case <OG:Chloroplast>
SUBCELLULAR LOCATIONPlastid, chloroplast thylakoid membrane; Multi- pass membrane protein.
else case <OC:Gloeobacter>
SUBCELLULAR LOCATIONCell inner membrane; Multi-pass membrane protein.
else
SUBCELLULAR LOCATIONCellular thylakoid membrane; Multi-pass membrane protein.
end case
SIMILARITYBelongs to the PsaA/PsaB family.

Keywords [?]

Transport
Electron transport
Photosynthesis
case <OC:Gloeobacter>
Cell membrane
Cell inner membrane
else
Thylakoid
end case
Photosystem I
Chromophore
Chlorophyll
Metal-binding
Iron
Oxidoreductase
Magnesium
Iron-sulfur
4Fe-4S
Membrane
Transmembrane
Transmembrane helix

Gene Ontology [?]

GO:0009055; Molecular function:electron transfer activity
GO:0000287; Molecular function:magnesium ion binding
GO:0015979; Biological process:photosynthesis
case <OG:Chloroplast>
GO:0009535; Cellular component:chloroplast thylakoid membrane
else case <OCellular component:Gloeobacter>
GO:0005886; Cellular component:plasma membrane
else; https://www.ebi.ac.uk/QuickGO/term/else
GO:0042651; Cellular component:thylakoid membrane
end case

Cross-references [?]

Pfam PF00223; PsaA_PsaB; 1;
PIRSF PIRSF002905; PSI_A; 1;
PRINTS PR00257; PHOTSYSPSAAB; 1;
NCBIfam TIGR01336; psaB; 1;
PROSITE PS00419; PHOTOSYSTEM_I_PSAAB; 1;

Features [?]

From: PSAB_THEVB (P0A407)
Key From To Description Tag Condition FTGroup
TRANSMEM 39 70 /note="Helical; Name=I"
TRANSMEM 132 156 /note="Helical; Name=II"
TRANSMEM 173 195 /note="Helical; Name=III"
TRANSMEM 270 287 /note="Helical; Name=IV"
TRANSMEM 335 358 /note="Helical; Name=V"
TRANSMEM 369 400 /note="Helical; Name=VI"
TRANSMEM 420 449 /note="Helical; Name=VII"
TRANSMEM 521 545 /note="Helical; Name=VIII"
TRANSMEM 579 610 /note="Helical; Name=IX"
TRANSMEM 651 672 /note="Helical; Name=X"
TRANSMEM 709 737 /note="Helical; Name=XI"
BINDING 566 566 /ligand="[4Fe-4S] cluster"
/ligand_id="ChEBI:CHEBI:49883"
/ligand_note="ligand shared between dimeric partners"		 C
BINDING 575 575 /ligand="[4Fe-4S] cluster"
/ligand_id="ChEBI:CHEBI:49883"
/ligand_note="ligand shared between dimeric partners"		 C
case not <OC:Prochlorococcus>
BINDING 661 661 /ligand="chlorophyll a"
/ligand_id="ChEBI:CHEBI:58416"
/ligand_label="B1"
/ligand_part="Mg"
/ligand_part_id="ChEBI:CHEBI:25107"
/note="axial binding residue"		 H
BINDING 669 669 /ligand="chlorophyll a"
/ligand_id="ChEBI:CHEBI:58416"
/ligand_label="B3"
/ligand_part="Mg"
/ligand_part_id="ChEBI:CHEBI:25107"
/note="axial binding residue"		 M
BINDING 677 677 /ligand="chlorophyll a"
/ligand_id="ChEBI:CHEBI:58416"
/ligand_label="B3"		 Y
else case <OC:Prochlorococcus>
BINDING 661 661 /ligand="divinyl chlorophyll a"
/ligand_id="ChEBI:CHEBI:73095"
/ligand_label="B1"
/ligand_part="Mg"
/ligand_part_id="ChEBI:CHEBI:25107"
/note="axial binding residue"		 H
BINDING 669 669 /ligand="divinyl chlorophyll a"
/ligand_id="ChEBI:CHEBI:73095"
/ligand_label="B3"
/ligand_part="Mg"
/ligand_part_id="ChEBI:CHEBI:25107"
/note="axial binding residue"		 M
BINDING 677 677 /ligand="divinyl chlorophyll a"
/ligand_id="ChEBI:CHEBI:73095"
/ligand_label="B3"		 Y
end case
BINDING 678 678 /ligand="phylloquinone"
/ligand_id="ChEBI:CHEBI:18067"
/ligand_label="B"		 W

Additional information [?]

Size range 644-776 amino acids
Related rules None
Fusion Nter: None Cter: <OmpA-like domain>
Comments G.violaceus is fused to an OmpA-like domain. AMPCA is atypical.



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