K9UMX2 · K9UMX2_CHAP6

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.

Catalytic activity

Features

Showing features for binding site, site.

TypeIDPosition(s)Description
Binding site182Mg (UniProtKB | ChEBI) of chlorophyll a ChlzD1 (UniProtKB | ChEBI); axial binding residue
Binding site190pheophytin a D1 (UniProtKB | ChEBI)
Site225Tyrosine radical intermediate
Binding site234[CaMn4O5] cluster (UniProtKB | ChEBI)
Binding site253[CaMn4O5] cluster (UniProtKB | ChEBI)
Site254Stabilizes free radical intermediate
Binding site262Mg (UniProtKB | ChEBI) of chlorophyll a PD1 (UniProtKB | ChEBI); axial binding residue
Binding site279Fe cation (UniProtKB | ChEBI); ligand shared with heterodimeric partner
Binding site279a quinone B (UniProtKB | ChEBI)
Binding site328-329a quinone B (UniProtKB | ChEBI)
Binding site336Fe cation (UniProtKB | ChEBI); ligand shared with heterodimeric partner
Binding site396[CaMn4O5] cluster (UniProtKB | ChEBI)
Binding site397[CaMn4O5] cluster (UniProtKB | ChEBI)
Binding site406[CaMn4O5] cluster (UniProtKB | ChEBI)
Binding site408[CaMn4O5] cluster (UniProtKB | ChEBI)
Site408-409Cleavage; 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
Molecular Functionoxygen evolving activity
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
      Cha6605_5282

Organism names

Accessions

  • Primary accession
    K9UMX2

Proteomes

Subcellular Location

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

Features

Showing features for transmembrane.

TypeIDPosition(s)Description
Transmembrane93-119Helical
Transmembrane175-193Helical
Transmembrane205-225Helical
Transmembrane262-282Helical
Transmembrane337-359Helical

Keywords

PTM/Processing

Features

Showing features for chain, propeptide.

TypeIDPosition(s)Description
ChainPRO_50233765321-408Photosystem II protein D1
PropeptidePRO_5007347382409-424

Post-translational modification

C-terminally processed by CtpA; processing is essential to allow assembly of the oxygen-evolving complex and thus photosynthetic growth.
Tyr-225 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.

Protein-protein interaction databases

Structure

Family & Domains

Sequence similarities

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

Keywords

Phylogenomic databases

Family and domain databases

Sequence

  • Sequence status
    Complete
  • Length
    424
  • Mass (Da)
    46,973
  • Last updated
    2013-03-06 v1
  • Checksum
    9DF4A1549BD3BB9C
MSPEIQLSSLCVQKMTRSPVITKPDDSHKVYKPEKGLQTLTIELNYVHTSKTFRSTRNTSNHKTMTTTLQRTQNANVWDRFCSWITSTENRIYVGWFGVLMVPTLLSATICFIIAFIAAPPVDIDGIREPVAGSLMFGNNIISGAVIPSSNAIGLHFYPIWEAASLDEWLYNGGPYQLVVFHFLIGIFCYMGREWELSYRLGMRPWICVAYSAPVAAATAVFLIYPIGQGSFSDGMPLGISGTFNFMIVFQAEHNILMHPFHMLGVAGVFGGSLFSAMHGSLVTSSLVRETTEVESQNYGYKFGQEEETYNIVAAHGYFGRLIFQYASFNNSRSLHFFLGAWPVVGIWFTSLGVSTMAFNLNGFNFNQSVVDSQGRGINTWADIINRANLGMEVMHERNAHNFPLDLAAGEATPVALTAPAING

Keywords

Sequence databases

Nucleotide SequenceProtein SequenceMolecule TypeStatus
CP003600
EMBL· GenBank· DDBJ
AFY96170.1
EMBL· GenBank· DDBJ
Genomic DNA

Genome annotation databases

Similar Proteins

Disclaimer

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