Q46IV6 · PSAA_PROMT
- ProteinPhotosystem I P700 chlorophyll a apoprotein A1
- GenepsaA
- StatusUniProtKB reviewed (Swiss-Prot)
- Amino acids768 (go to sequence)
- Protein existenceInferred from homology
- Annotation score3/5
Function
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.
Catalytic activity
- reduced [plastocyanin] + hnu + oxidized [2Fe-2S]-[ferredoxin] = oxidized [plastocyanin] + reduced [2Fe-2S]-[ferredoxin]
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.
Features
Showing features for binding site.
Type | ID | Position(s) | Description | ||
---|---|---|---|---|---|
Binding site | 601 | [4Fe-4S] cluster (UniProtKB | ChEBI); ligand shared between dimeric partners | |||
Binding site | 610 | [4Fe-4S] cluster (UniProtKB | ChEBI); ligand shared between dimeric partners | |||
Binding site | 693 | Mg (UniProtKB | ChEBI) of divinylchlorophyll a' A1 (UniProtKB | ChEBI); axial binding residue | |||
Binding site | 701 | Mg (UniProtKB | ChEBI) of divinyl chlorophyll a A3 (UniProtKB | ChEBI); axial binding residue | |||
Binding site | 709 | divinyl chlorophyll a A3 (UniProtKB | ChEBI) | |||
Binding site | 710 | phylloquinone A (UniProtKB | ChEBI) | |||
GO annotations
Aspect | Term | |
---|---|---|
Cellular Component | photosystem I | |
Cellular Component | plasma membrane-derived thylakoid membrane | |
Molecular Function | 4 iron, 4 sulfur cluster binding | |
Molecular Function | chlorophyll binding | |
Molecular Function | electron transfer activity | |
Molecular Function | magnesium ion binding | |
Molecular Function | oxidoreductase activity | |
Biological Process | photosynthesis |
Keywords
- Molecular function
- Biological process
- Ligand
Enzyme and pathway databases
Names & Taxonomy
Protein names
- Recommended namePhotosystem I P700 chlorophyll a apoprotein A1
- EC number
- Alternative names
Gene names
Organism names
- Strain
- Taxonomic lineageBacteria > Cyanobacteriota > Cyanophyceae > Synechococcales > Prochlorococcaceae > Prochlorococcus
Accessions
- Primary accessionQ46IV6
Proteomes
Subcellular Location
UniProt Annotation
GO Annotation
Cellular thylakoid membrane ; Multi-pass membrane protein
Features
Showing features for transmembrane.
Type | ID | Position(s) | Description | ||
---|---|---|---|---|---|
Transmembrane | 76-99 | Helical; Name=I | |||
Transmembrane | 162-185 | Helical; Name=II | |||
Transmembrane | 201-225 | Helical; Name=III | |||
Transmembrane | 310-328 | Helical; Name=IV | |||
Transmembrane | 369-392 | Helical; Name=V | |||
Transmembrane | 408-434 | Helical; Name=VI | |||
Transmembrane | 456-478 | Helical; Name=VII | |||
Transmembrane | 559-577 | Helical; Name=VIII | |||
Transmembrane | 617-638 | Helical; Name=IX | |||
Transmembrane | 682-704 | Helical; Name=X | |||
Transmembrane | 742-762 | Helical; Name=XI | |||
Keywords
- Cellular component
PTM/Processing
Features
Showing features for chain.
Type | ID | Position(s) | Description | ||
---|---|---|---|---|---|
Chain | PRO_0000294205 | 1-768 | Photosystem I P700 chlorophyll a apoprotein A1 | ||
Interaction
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.
Protein-protein interaction databases
Structure
Sequence
- Sequence statusComplete
- Length768
- Mass (Da)84,363
- Last updated2005-09-13 v1
- MD5 Checksum0D047014134A643F94D6A6B52C54C046
Keywords
- Technical term
Sequence databases
Nucleotide Sequence | Protein Sequence | Molecule Type | Status | |
---|---|---|---|---|
CP000095 EMBL· GenBank· DDBJ | AAZ58572.1 EMBL· GenBank· DDBJ | Genomic DNA |