Q5SCW8 · PSBA_HUPLU

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.
Herbicides such as atrazine, BNT, diuron or ioxynil bind in the Q(B) binding site and block subsequent electron transfer.

Catalytic activity

Cofactor

Note: The D1/D2 heterodimer binds P680, chlorophylls that are the primary electron donor of PSII, and subsequent electron acceptors. It shares a non-heme iron and each subunit binds pheophytin, quinone, additional chlorophylls, carotenoids and lipids. D1 provides most of the ligands for the Mn4-Ca-O5 cluster of the oxygen-evolving complex (OEC). There is also a Cl-1 ion associated with D1 and D2, which is required for oxygen evolution. The PSII complex binds additional chlorophylls, carotenoids and specific lipids.

Features

Showing features for binding site, site.

Type
IDPosition(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 site215a quinone B (UniProtKB | ChEBI)
Binding site215Fe cation (UniProtKB | ChEBI); ligand shared with heterodimeric partner
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 Componentchloroplast thylakoid membrane
Cellular Componentphotosystem II
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

Encoded on

  • Chloroplast

Organism names

Accessions

  • Primary accession
    Q5SCW8

Subcellular Location

Features

Showing features for transmembrane.

TypeIDPosition(s)Description
Transmembrane29-46Helical
Transmembrane118-133Helical
Transmembrane142-156Helical
Transmembrane197-218Helical
Transmembrane274-288Helical

Keywords

PTM/Processing

Features

Showing features for initiator methionine, modified residue, chain, propeptide.

Type
IDPosition(s)Description
Initiator methionine1Removed
Modified residue2N-acetylthreonine
Modified residue2Phosphothreonine
ChainPRO_00003399992-344Photosystem II protein D1
PropeptidePRO_0000340000345-353

Post-translational modification

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

Keywords

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, at least 3 peripheral proteins of the oxygen-evolving complex and a large number of cofactors. It forms dimeric complexes.

Structure

Family & Domains

Sequence similarities

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

Keywords

Family and domain databases

Sequence

  • Sequence status
    Complete
  • Sequence processing
    The displayed sequence is further processed into a mature form.
  • Length
    353
  • Mass (Da)
    38,735
  • Last updated
    2004-12-21 v1
  • Checksum
    E63DAE08F69DC97F
MTATLERRESASLWGRFCDWVTSTENRLYIGWFGVLMIPTLLTATAVFIIAFIAAPPVDIDGIREPVSGSLLYGNNIISGAIIPTSAAIGLHFYPIWEAASVDEWLYNGGPYELIVLHFLLGVACYMGREWELSFRLGMRPWIAVAYSAPVAAAAAVFLIYPIGQGSFSDGMPLGISGTFNFMIVFQAEHNILMHPFHMLGVAGVFGGSLFSAMHGSLVTSSLIRETTENESANAGYKFGQEEETYNIVAAHGYFGRLIFQYASFNNSRSLHFFLAAWPVVGIWFTALGISTMAFNLNGFNFNQSVVDSQGRVINTWADIINRANLGMEVMHERNAHNFPLDLASVEAPSVNG

Sequence databases

Nucleotide SequenceProtein SequenceMolecule TypeStatus
AY660566
EMBL· GenBank· DDBJ
AAT80732.1
EMBL· GenBank· DDBJ
Genomic DNA

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.
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