A0A2S6CPX1 · A0A2S6CPX1_9CYAN
- ProteinPhotosystem I P700 chlorophyll a apoprotein A1
- GenepsaA
- StatusUniProtKB unreviewed (TrEMBL)
- Amino acids751 (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.
PsaA and psaB bind P700, the primary electron donor of photosystem I (PSI), as well as the electron acceptors A0, A1 and FX.
Catalytic activity
- hnu + oxidized [2Fe-2S]-[ferredoxin] + reduced [plastocyanin] = oxidized [plastocyanin] + reduced [2Fe-2S]-[ferredoxin]
Features
Showing features for binding site.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Binding site | 575 | [4Fe-4S] cluster (UniProtKB | ChEBI); ligand shared between dimeric partners | ||||
Sequence: C | ||||||
Binding site | 584 | [4Fe-4S] cluster (UniProtKB | ChEBI); ligand shared between dimeric partners | ||||
Sequence: C | ||||||
Binding site | 676 | Mg (UniProtKB | ChEBI) of chlorophyll a' A1 (UniProtKB | ChEBI); axial binding residue | ||||
Sequence: H | ||||||
Binding site | 684 | Mg (UniProtKB | ChEBI) of chlorophyll a A3 (UniProtKB | ChEBI); axial binding residue | ||||
Sequence: M | ||||||
Binding site | 692 | chlorophyll a A3 (UniProtKB | ChEBI) | ||||
Sequence: Y | ||||||
Binding site | 693 | phylloquinone A (UniProtKB | ChEBI) | ||||
Sequence: W |
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 > Nostocales > Aphanizomenonaceae > Cuspidothrix
Accessions
- Primary accessionA0A2S6CPX1
Proteomes
Subcellular Location
UniProt Annotation
GO Annotation
Cellular thylakoid membrane ; Multi-pass membrane protein
Membrane ; Multi-pass membrane protein
Features
Showing features for transmembrane.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Transmembrane | 73-93 | Helical | ||||
Sequence: IFAAHFGHLAVVAIWLSGMLF | ||||||
Transmembrane | 157-181 | Helical | ||||
Sequence: FQLYVTAIGGLVLAGLFLFAGWFHY | ||||||
Transmembrane | 294-312 | Helical | ||||
Sequence: ISHHHLAIAVLFIIAGHMY | ||||||
Transmembrane | 353-373 | Helical | ||||
Sequence: LATNLAFLGSLTIIIAHHMYA | ||||||
Transmembrane | 393-415 | Helical | ||||
Sequence: HHIWIGGFLIVGGAAHAAIFMVR | ||||||
Transmembrane | 436-457 | Helical | ||||
Sequence: AIISHLNWVCIFLGFHSFGLYI | ||||||
Transmembrane | 538-557 | Helical | ||||
Sequence: IHAFTIHVTVLILLKGVLYA | ||||||
Transmembrane | 592-612 | Helical | ||||
Sequence: IFLGLFWMYNSLSIVIFHFSW | ||||||
Transmembrane | 665-687 | Helical | ||||
Sequence: LSAYGLMFLGAHFVWAFSLMFLF |
Keywords
- Cellular component
Interaction
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.
Structure
Sequence
- Sequence statusComplete
- Length751
- Mass (Da)83,008
- Last updated2018-07-18 v1
- Checksum5C704265DB9323A9
Keywords
- Technical term