A0A9X5E388 · A0A9X5E388_9CYAN

Function

function

Photosystem II (PSII) is a light-driven water:plastoquinone oxidoreductase that uses light energy to abstract electrons from H2O, generating O2 and a proton gradient subsequently used for ATP formation. It consists of a core antenna complex that captures photons, and an electron transfer chain that converts photonic excitation into a charge separation. The D1/D2 (PsbA/PsbD) reaction center heterodimer binds P680, the primary electron donor of PSII as well as several subsequent electron acceptors.

Miscellaneous

2 of the reaction center chlorophylls (ChlD1 and ChlD2) are entirely coordinated by water.
Cyanobacteriota usually contain more than 2 copies of the psbA gene.
Herbicides such as atrazine, BNT, diuron or ioxynil bind in the Q(B) binding site and block subsequent electron transfer.

Caution

The sequence shown here is derived from an EMBL/GenBank/DDBJ whole genome shotgun (WGS) entry which is preliminary data.

Catalytic activity

Features

Showing features for binding site, site.

TypeIDPosition(s)Description
Binding site118Mg (UniProtKB | ChEBI) of chlorophyll a ChlzD1 (UniProtKB | ChEBI); axial binding residue
Binding site126pheophytin a D1 (UniProtKB | ChEBI)
Site161Tyrosine radical intermediate
Binding site170[CaMn4O5] cluster (UniProtKB | ChEBI)
Binding site189[CaMn4O5] cluster (UniProtKB | ChEBI)
Site190Stabilizes free radical intermediate
Binding site198Mg (UniProtKB | ChEBI) of chlorophyll a PD1 (UniProtKB | ChEBI); axial binding residue
Binding site215Fe cation (UniProtKB | ChEBI); ligand shared with heterodimeric partner
Binding site215a quinone B (UniProtKB | ChEBI)
Binding site264-265a quinone B (UniProtKB | ChEBI)
Binding site272Fe cation (UniProtKB | ChEBI); ligand shared with heterodimeric partner
Binding site332[CaMn4O5] cluster (UniProtKB | ChEBI)
Binding site333[CaMn4O5] cluster (UniProtKB | ChEBI)
Binding site342[CaMn4O5] cluster (UniProtKB | ChEBI)
Binding site344[CaMn4O5] cluster (UniProtKB | ChEBI)
Site344-345Cleavage; by CtpA

GO annotations

AspectTerm
Cellular Componentphotosystem II
Cellular Componentplasma membrane-derived thylakoid membrane
Molecular Functionchlorophyll binding
Molecular Functionelectron transporter, transferring electrons within the cyclic electron transport pathway of photosynthesis activity
Molecular Functioniron ion binding
Molecular Functionoxidoreductase activity, acting on diphenols and related substances as donors, oxygen as acceptor
Biological Processphotosynthetic electron transport in photosystem II
Biological Processresponse to herbicide

Keywords

Enzyme and pathway databases

Names & Taxonomy

Protein names

  • Recommended name
    Photosystem II protein D1
  • EC number
  • Short names
    PSII D1 protein
  • Alternative names
    • Photosystem II Q(B) protein

Gene names

    • Name
      psbA
    • ORF names
      QH73_0006200
      , QH73_0012355

Organism names

  • Taxonomic identifier
  • Strain
    • VB511283
  • Taxonomic lineage
    Bacteria > Cyanobacteriota > Cyanophyceae > Nostocales > Scytonemataceae > Scytonema

Accessions

  • Primary accession
    A0A9X5E388

Proteomes

Subcellular Location

Cellular thylakoid membrane
; Multi-pass membrane protein
Membrane
; Multi-pass membrane protein

Features

Showing features for transmembrane.

TypeIDPosition(s)Description
Transmembrane29-55Helical
Transmembrane109-127Helical
Transmembrane139-160Helical
Transmembrane200-218Helical
Transmembrane270-295Helical

Keywords

PTM/Processing

Features

Showing features for chain, propeptide.

TypeIDPosition(s)Description
ChainPRO_50410239091-344Photosystem II protein D1
PropeptidePRO_5041023908345-353

Post-translational modification

C-terminally processed by CtpA; processing is essential to allow assembly of the oxygen-evolving complex and thus photosynthetic growth.
Tyr-161 forms a radical intermediate that is referred to as redox-active TyrZ, YZ or Y-Z.

Interaction

Subunit

PSII is composed of 1 copy each of membrane proteins PsbA, PsbB, PsbC, PsbD, PsbE, PsbF, PsbH, PsbI, PsbJ, PsbK, PsbL, PsbM, PsbT, PsbX, PsbY, PsbZ, Psb30/Ycf12, peripheral proteins PsbO, CyanoQ (PsbQ), PsbU, PsbV and a large number of cofactors. It forms dimeric complexes.

Family & Domains

Sequence similarities

Belongs to the reaction center PufL/M/PsbA/D family.

Keywords

Family and domain databases

Sequence

  • Sequence status
    Complete
  • Length
    353
  • Mass (Da)
    38,965
  • Last updated
    2023-11-08 v1
  • Checksum
    FBAE51EBB50A1C1D
MTTTLQRRESASLWEQFCNWVASTENRLYIGWFGVLMIPTLLAATTCFIVAFIAAPPVDIDGIREPVAGSLIYGNNIISGAVVPSSNAIGLHFYPIWEAASLDEWLYNGGPYQLVIFHFLIGVFCYMGREWELSYRLGMRPWICVAYSAPVAAATAVFLIYPIGQGSFSDGMPLGISGTFNFMLVFQAEHNILMHPFHQLGVAGVFGGALFSAMHGSLVTSSLVRETTETESQNYGYKFGQEEETYNIVAAHGYFGRLIFQYASFNNSRALHFFLAAWPVIGIWFTSLGISTMAFNLNGFNFNQSVVDSQGHAIGTWADILNRANLGMEVMHERNAHNFPLDLAAVEAPSLNG

Sequence databases

Nucleotide SequenceProtein SequenceMolecule TypeStatus
JTJC03000001
EMBL· GenBank· DDBJ
NHC34252.1
EMBL· GenBank· DDBJ
Genomic DNA
JTJC03000003
EMBL· GenBank· DDBJ
NHC35440.1
EMBL· GenBank· DDBJ
Genomic DNA

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.
We'd like to inform you that we have updated our Privacy Notice to comply with Europe’s new General Data Protection Regulation (GDPR) that applies since 25 May 2018.
FeedbackHelp