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Q6B8U6 · PSAA_GRATL

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: 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 site575[4Fe-4S] cluster (UniProtKB | ChEBI); ligand shared between dimeric partners
Binding site584[4Fe-4S] cluster (UniProtKB | ChEBI); ligand shared between dimeric partners
Binding site677Mg (UniProtKB | ChEBI) of chlorophyll a' A1 (UniProtKB | ChEBI); axial binding residue
Binding site685Mg (UniProtKB | ChEBI) of chlorophyll a A3 (UniProtKB | ChEBI); axial binding residue
Binding site693chlorophyll a A3 (UniProtKB | ChEBI)
Binding site694phylloquinone A (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 A1
  • EC number
  • Alternative names
    • PSI-A
    • PsaA

Gene names

    • Name
      psaA
    • Ordered locus names
      Grc000108

Encoded on

  • Chloroplast

Organism names

Accessions

  • Primary accession
    Q6B8U6

Subcellular Location

Features

Showing features for transmembrane.

TypeIDPosition(s)Description
Transmembrane73-96Helical; Name=I
Transmembrane159-182Helical; Name=II
Transmembrane198-222Helical; Name=III
Transmembrane294-312Helical; Name=IV
Transmembrane349-372Helical; Name=V
Transmembrane388-414Helical; Name=VI
Transmembrane436-458Helical; Name=VII
Transmembrane533-551Helical; Name=VIII
Transmembrane591-612Helical; Name=IX
Transmembrane666-688Helical; Name=X
Transmembrane726-746Helical; Name=XI

Keywords

PTM/Processing

Features

Showing features for chain.

TypeIDPosition(s)Description
ChainPRO_00000885511-752Photosystem 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 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
    752
  • Mass (Da)
    83,604
  • Last updated
    2005-06-21 v2
  • MD5 Checksum
    3203B6468945313ECC035423D8386D50
MTISSQEQETKKVQVTVDKNPVATSFEKWAKPGHFSRTLAKGPKTTTWIWNLHADAHDFDSHTSSLEEVSRKIFSAHFGQLAIIFLWLSGMYFHGAKFSNYIAWLSNPTAIKPSAQIVWPIVGQEILNGDVGGGFQGVQITSGFFQIWRASGITTEFELYATAIGGLFMACLMLFAGWFHYHKAAPKLEWFQNVESMMNHHLAGLLGLGCLGWAGHQIHISIPINKLLDSGVSPQELPLPHEFLVNRELVSQLYPSFSKGIIPFFTLNWNEYSDFLTFKGGLNPITGGLWLTDTAHHHLALAVLFLVAGHMYRTNWGIGHSMKEILEAHKGPFTGEGHKGIYEILTTSWHAQLAINLAMMGSLSIIVAHHMYAMPPYPYIATDYPTQLSLFTHHMWIGGFCIVGAGAHASIFMVRDYNPAQNYNNVLDRVIRHRDAIISHLNWVCIFLGFHSFGLYIHNDTMRALGRSQDMFSDTAIQLQPIFAQWIQNIHSLAPSNTSPNALATASYAFGGDVIAVNNKIAMMPINLGTADFMVHHIHAFTIHVTVLILVKGFLFSRNSRLIPDKSSLGFRFPCDGPGRGGTCQVSGWDHVFLGLFWMYNSLSIAIFHFSWKMQSDVWGSVTPAGTVSHITGGNFAQSAITINGWLRDFLWAQASQVIQSYGSALSAYGLIFLGAHFVWAFSLMFLFSGRGYWQELIESIVWAHNKVKVAPSIQPRALSITQGRAVGVAHYLLGGIGTTWAFFLARIISVG

Sequence caution

The sequence AAT79689.1 differs from that shown. Reason: Erroneous initiation

Sequence databases

Nucleotide SequenceProtein SequenceMolecule TypeStatus
AY673996
EMBL· GenBank· DDBJ
AAT79689.1
EMBL· GenBank· DDBJ
Genomic DNA Different initiation

Genome annotation databases

Similar Proteins

Disclaimer

Any medical or genetic information present in this entry is provided for research, educational and informational purposes only. It is not in any way intended to be used as a substitute for professional medical advice, diagnosis, treatment or care. Our staff consists of biologists and biochemists that are not trained to give medical advice.
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