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HAMAP rule MF_00458

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General rule information [?]

Accession MF_00458
Dates 1-JUN-2001 (Created)
17-FEB-2023 (Last updated, Version 64)
Name PSI_PsaA
Scope
Bacteria; Cyanobacteriota
Plastid
Templates P12154 (PSAA_CHLRE); P06511 (PSAA_SPIOL); P0A405 (PSAA_THEVB); P0A406 (PSAA_SYNEL): [Recover all]
Triggered by

Propagated annotation [?]


Identifier, protein and gene names [?]

Identifier
PSAA
case not <OG:Chloroplast>
Protein name
RecName: Full=Photosystem I P700 chlorophyll a apoprotein A1;
EC 1.97.1.12;
AltName: Full=PsaA;
else case <OG:Chloroplast>
Protein name
RecName: Full=Photosystem I P700 chlorophyll a apoprotein A1;
EC 1.97.1.12;
AltName: Full=PSI-A;
AltName: Full=PsaA;
end case
Gene name
psaA

Comments [?]

case <OC:Cyanobacteriota> or <OG:Chloroplast> and not <OC:Streptophyta>
Function 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.
else case <OG:Chloroplast> and <OC:Streptophyta>
Function 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.
end case
Catalytic activity RHEA:30407: hnu + oxidized [2Fe-2S]-[ferredoxin] + reduced [plastocyanin] = oxidized [plastocyanin] + reduced [2Fe-2S]-[ferredoxin]
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.
Subunit 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.
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.
Subunit The 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.
Subunit 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 eukaryotic PSI reaction center is composed of at least 11 subunits.
end case
case <OG:Chloroplast>
Subcellular location Plastid, chloroplast thylakoid membrane; Multi-pass membrane protein.
else case <OC:Gloeobacter>
Subcellular location Cell inner membrane; Multi-pass membrane protein.
else
Subcellular location Cellular thylakoid membrane; Multi-pass membrane protein.
end case
Similarity Belongs 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
Oxidoreductase
Metal-binding
Iron
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 <OC:Gloeobacter>
GO:0005886; Cellular component: plasma membrane.
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;
TIGRFAMs TIGR01335; PsaA; 1;
PROSITE PS00419; PHOTOSYSTEM_I_PSAAB; 1;

Features [?]

From: PSAA_THEVB (P0A405)
Key     From     To       Description   Tag   Condition   FTGroup
TRANSMEM     72     95       Helical; Name=I        
TRANSMEM     158     181       Helical; Name=II        
TRANSMEM     197     221       Helical; Name=III        
TRANSMEM     297     315       Helical; Name=IV        
TRANSMEM     352     375       Helical; Name=V        
TRANSMEM     391     417       Helical; Name=VI        
TRANSMEM     439     461       Helical; Name=VII        
TRANSMEM     536     554       Helical; Name=VIII        
TRANSMEM     594     615       Helical; Name=IX        
TRANSMEM     669     691       Helical; Name=X        
TRANSMEM     729     749       Helical; Name=XI        
BINDING     578     578       /ligand="[4Fe-4S] cluster" /ligand_id="ChEBI:CHEBI:49883" /ligand_note="ligand shared between dimeric partners     C  
BINDING     587     587       /ligand="[4Fe-4S] cluster" /ligand_id="ChEBI:CHEBI:49883" /ligand_note="ligand shared between dimeric partners     C  
case not <OC:Prochlorococcus>
BINDING     680     680       /ligand="chlorophyll a'" /ligand_id="ChEBI:CHEBI:189419" /ligand_label="A1" /ligand_part="Mg" /ligand_part_id="ChEBI:CHEBI:25107" /note="axial binding residue     H  
BINDING     688     688       /ligand="chlorophyll a" /ligand_id="ChEBI:CHEBI:58416" /ligand_label="A3" /ligand_part="Mg" /ligand_part_id="ChEBI:CHEBI:25107" /note="axial binding residue     M  
BINDING     696     696       /ligand="chlorophyll a" /ligand_id="ChEBI:CHEBI:58416" /ligand_label="A3     Y  
end case
case <OC:Prochlorococcus>
BINDING     680     680       /ligand="divinylchlorophyll a'" /ligand_id="ChEBI:CHEBI:189420" /ligand_label="A1" /ligand_part="Mg" /ligand_part_id="ChEBI:CHEBI:25107" /note="axial binding residue     H  
BINDING     688     688       /ligand="divinyl chlorophyll a" /ligand_id="ChEBI:CHEBI:73095" /ligand_label="A3" /ligand_part="Mg" /ligand_part_id="ChEBI:CHEBI:25107" /note="axial binding residue     M  
BINDING     696     696       /ligand="divinyl chlorophyll a" /ligand_id="ChEBI:CHEBI:73095" /ligand_label="A3     Y  
end case
BINDING     697     697       /ligand="phylloquinone" /ligand_id="ChEBI:CHEBI:18067" /ligand_label="A     W  

Additional information [?]

Size range 678-783 amino acids
Related rules None
Fusion None


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