Q8M9V9 · PSAB_CHAGL

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-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.

Catalytic activity

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.

Features

Showing features for binding site.

TypeIDPosition(s)Description
Binding site559[4Fe-4S] cluster (UniProtKB | ChEBI); ligand shared between dimeric partners
Binding site568[4Fe-4S] cluster (UniProtKB | ChEBI); ligand shared between dimeric partners
Binding site654Mg (UniProtKB | ChEBI) of chlorophyll a B1 (UniProtKB | ChEBI); axial binding residue
Binding site662Mg (UniProtKB | ChEBI) of chlorophyll a B3 (UniProtKB | ChEBI); axial binding residue
Binding site670chlorophyll a B3 (UniProtKB | ChEBI)
Binding site671phylloquinone B (UniProtKB | ChEBI)

GO annotations

AspectTerm
Cellular Componentchloroplast thylakoid membrane
Cellular Componentphotosystem I
Molecular Function4 iron, 4 sulfur cluster binding
Molecular Functionchlorophyll binding
Molecular Functionelectron transfer activity
Molecular Functionmagnesium ion binding
Molecular Functionoxidoreductase activity
Biological Processphotosynthesis

Keywords

Enzyme and pathway databases

Names & Taxonomy

Protein names

  • Recommended name
    Photosystem I P700 chlorophyll a apoprotein A2
  • EC number
  • Alternative names
    • PSI-B
    • PsaB

Gene names

    • Name
      psaB

Encoded on

  • Chloroplast

Organism names

Accessions

  • Primary accession
    Q8M9V9

Subcellular Location

Features

Showing features for transmembrane.

TypeIDPosition(s)Description
Transmembrane46-69Helical; Name=I
Transmembrane135-158Helical; Name=II
Transmembrane175-199Helical; Name=III
Transmembrane273-291Helical; Name=IV
Transmembrane330-353Helical; Name=V
Transmembrane369-395Helical; Name=VI
Transmembrane417-439Helical; Name=VII
Transmembrane517-535Helical; Name=VIII
Transmembrane575-596Helical; Name=IX
Transmembrane643-665Helical; Name=X
Transmembrane707-727Helical; Name=XI

Keywords

PTM/Processing

Features

Showing features for chain.

TypeIDPosition(s)Description
ChainPRO_00000886071-734Photosystem I P700 chlorophyll a apoprotein A2

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 eukaryotic PSI reaction center is composed of at least 11 subunits.

Structure

Family & Domains

Sequence similarities

Belongs to the PsaA/PsaB family.

Keywords

Family and domain databases

Sequence

  • Sequence status
    Complete
  • Length
    734
  • Mass (Da)
    81,925
  • Last updated
    2002-10-01 v1
  • Checksum
    4F39D1E66489A11B
MASRFPKFSQGLSQDPTTRRIWFGIATAHDFESHDGITEEKLYQKIFASHFGQLAVIFLWTSGNLFHVAWQGNFEAWSQDPLHVRPIAHAIWDPHFGQPAVEAFTRGGASGPVNISYSGVYQWWYTQGIRTNLELYQGALFLLGLAAVSLAAGWLHLQPKWQPKISWFKNAESRLNHHLSGLFGVSSLAWSGHLVHVAIPESRGQHVGWDNLLTTLPHPAGLAPFFSGQWSVYSQNPDSASHLFSTSQGSGTAILTFLGGFHPQTQSLWLTDIAHHHLAIAVLFIIAGHQYRTNFGIGHSIREILESHVPPGGGLGQGHKGLYDTLNNSLHFQLGLALASLGVITSLVAQHMYSLPSYAFIAQDFTTQAALYTHHQYIAGFIMSGAFAHGAIFFIRDYNPEQNKGNVLARMLEHKEAIISHLSWASLFLGFHTLGLYVHNDVVQAFGNPEKQILIEPVFAQWIQSSHGKTLYGFDVFLSSTASPAFYAGQSLWLPGWLDSINSNTNSLFLTIGPGDFLVHHAIALGLHTTTLILVKGALDARGSKLMPDKKEFGYSFPCDGPGRGGTCDISAWDAFYLAIFWMLNTIGWVTFYWHWKHLALWQGNAAQFNESSTYLMGWLRDYLWLNSSQLINGYNPFGMNSLSVWAWMFLFGHLIWATGFMFLISWRGYWQELIETLAWAHERTPLANLVRWKDKPVALSIVQARLVGLAHFSVGYIFTYAAFLIASTSGKFG

Sequence databases

Nucleotide SequenceProtein SequenceMolecule TypeStatus
AF494278
EMBL· GenBank· DDBJ
AAM96533.1
EMBL· GenBank· DDBJ
Genomic DNA

Genome annotation databases

Similar Proteins

Disclaimer

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