P0A405 · PSAA_THEVB

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

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.

Features

Showing features for binding site.

TypeIDPosition(s)Description
Binding site578[4Fe-4S] cluster (UniProtKB | ChEBI); ligand shared between dimeric partners
Binding site587[4Fe-4S] cluster (UniProtKB | ChEBI); ligand shared between dimeric partners
Binding site680Mg (UniProtKB | ChEBI) of chlorophyll a' A1 (UniProtKB | ChEBI); axial binding residue
Binding site688Mg (UniProtKB | ChEBI) of chlorophyll a A3 (UniProtKB | ChEBI); axial binding residue
Binding site696chlorophyll a A3 (UniProtKB | ChEBI)
Binding site697phylloquinone A (UniProtKB | ChEBI)

GO annotations

AspectTerm
Cellular Componentphotosystem I
Cellular Componentplasma membrane-derived thylakoid membrane
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 A1
  • EC number
  • Alternative names
    • PsaA

Gene names

    • Name
      psaA
    • Ordered locus names
      tlr0731

Organism names

Accessions

  • Primary accession
    P0A405
  • Secondary accessions
    • P25896

Proteomes

Subcellular Location

Features

Showing features for topological domain, transmembrane.

TypeIDPosition(s)Description
Topological domain1-64Cytoplasmic
Transmembrane65-96Helical; Name=I
Topological domain97-155Lumenal, thylakoid
Transmembrane156-179Helical; Name=II
Topological domain180-192Cytoplasmic
Transmembrane193-217Helical; Name=III
Topological domain218-293Lumenal, thylakoid
Transmembrane294-311Helical; Name=IV
Topological domain312-352Cytoplasmic
Transmembrane353-376Helical; Name=V
Topological domain377-386Lumenal, thylakoid
Transmembrane387-418Helical; Name=VI
Topological domain419-436Cytoplasmic
Transmembrane437-468Helical; Name=VII
Topological domain469-532Lumenal, thylakoid
Transmembrane533-558Helical; Name=VIII
Topological domain559-590Cytoplasmic
Transmembrane591-619Helical; Name=IX
Topological domain620-668Lumenal, thylakoid
Transmembrane669-690Helical; Name=X
Topological domain691-723Cytoplasmic
Transmembrane724-753Helical; Name=XI

Keywords

PTM/Processing

Features

Showing features for chain.

TypeIDPosition(s)Description
ChainPRO_00000885911-755Photosystem I P700 chlorophyll a apoprotein A1

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.

Protein-protein interaction databases

Family & Domains

Sequence similarities

Belongs to the PsaA/PsaB family.

Keywords

Phylogenomic databases

Family and domain databases

Sequence

  • Sequence status
    Complete
  • Length
    755
  • Mass (Da)
    83,183
  • Last updated
    2005-03-15 v1
  • Checksum
    36A39CCE5D119AEA
MTISPPEREPKVRVVVDNDPVPTSFEKWAKPGHFDRTLARGPQTTTWIWNLHALAHDFDTHTSDLEDISRKIFSAHFGHLAVVFIWLSGMYFHGAKFSNYEAWLADPTGIKPSAQVVWPIVGQGILNGDVGGGFHGIQITSGLFQLWRASGITNEFQLYCTAIGGLVMAGLMLFAGWFHYHKRAPKLEWFQNVESMLNHHLAGLLGLGSLAWAGHQIHVSLPINKLLDAGVAAKDIPLPHEFILNPSLMAELYPKVDWGFFSGVIPFFTFNWAAYSDFLTFNGGLNPVTGGLWLSDTAHHHLAIAVLFIIAGHMYRTNWGIGHSLKEILEAHKGPFTGAGHKGLYEVLTTSWHAQLAINLAMMGSLSIIVAQHMYAMPPYPYLATDYPTQLSLFTHHMWIGGFLVVGGAAHGAIFMVRDYDPAMNQNNVLDRVLRHRDAIISHLNWVCIFLGFHSFGLYVHNDTMRAFGRPQDMFSDTGIQLQPVFAQWVQNLHTLAPGGTAPNAAATASVAFGGDVVAVGGKVAMMPIVLGTADFMVHHIHAFTIHVTVLILLKGVLFARSSRLIPDKANLGFRFPCDGPGRGGTCQVSGWDHVFLGLFWMYNCISVVIFHFSWKMQSDVWGTVAPDGTVSHITGGNFAQSAITINGWLRDFLWAQASQVIGSYGSALSAYGLLFLGAHFIWAFSLMFLFSGRGYWQELIESIVWAHNKLKVAPAIQPRALSIIQGRAVGVAHYLLGGIATTWAFFLARIISVG

Sequence caution

The sequence BAC08282.1 differs from that shown. Reason: Erroneous initiation Extended N-terminus.

Keywords

Sequence databases

Nucleotide SequenceProtein SequenceMolecule TypeStatus
BA000039
EMBL· GenBank· DDBJ
BAC08282.1
EMBL· GenBank· DDBJ
Genomic DNA Different initiation

Genome annotation databases

Similar Proteins

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