Q5SCW8 · PSBA_HUPLU
- ProteinPhotosystem II protein D1
- GenepsbA
- StatusUniProtKB reviewed (Swiss-Prot)
- Amino acids353 (go to sequence)
- Protein existenceInferred from homology
- Annotation score4/5
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
- 2 a plastoquinone + 4 hnu + 2 H2O = 2 a plastoquinol + O2
2 a plastoquinone RHEA-COMP:9562 + 4 CHEBI:30212 + 2 CHEBI:15377 = 2 a plastoquinol RHEA-COMP:9561 + CHEBI:15379
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 | ID | Position(s) | Description | ||
---|---|---|---|---|---|
Binding site | 118 | Mg (UniProtKB | ChEBI) of chlorophyll a ChlzD1 (UniProtKB | ChEBI); axial binding residue | |||
Binding site | 126 | pheophytin a D1 (UniProtKB | ChEBI) | |||
Site | 161 | Tyrosine radical intermediate | |||
Binding site | 170 | [CaMn4O5] cluster (UniProtKB | ChEBI) | |||
Binding site | 189 | [CaMn4O5] cluster (UniProtKB | ChEBI) | |||
Site | 190 | Stabilizes free radical intermediate | |||
Binding site | 198 | Mg (UniProtKB | ChEBI) of chlorophyll a PD1 (UniProtKB | ChEBI); axial binding residue | |||
Binding site | 215 | a quinone B (UniProtKB | ChEBI) | |||
Binding site | 215 | Fe cation (UniProtKB | ChEBI); ligand shared with heterodimeric partner | |||
Binding site | 264-265 | a quinone B (UniProtKB | ChEBI) | |||
Binding site | 272 | Fe cation (UniProtKB | ChEBI); ligand shared with heterodimeric partner | |||
Binding site | 332 | [CaMn4O5] cluster (UniProtKB | ChEBI) | |||
Binding site | 333 | [CaMn4O5] cluster (UniProtKB | ChEBI) | |||
Binding site | 342 | [CaMn4O5] cluster (UniProtKB | ChEBI) | |||
Binding site | 344 | [CaMn4O5] cluster (UniProtKB | ChEBI) | |||
Site | 344-345 | Cleavage; by CTPA | |||
GO annotations
Aspect | Term | |
---|---|---|
Cellular Component | chloroplast thylakoid membrane | |
Cellular Component | photosystem II | |
Molecular Function | chlorophyll binding | |
Molecular Function | electron transporter, transferring electrons within the cyclic electron transport pathway of photosynthesis activity | |
Molecular Function | iron ion binding | |
Molecular Function | oxidoreductase activity, acting on diphenols and related substances as donors, oxygen as acceptor | |
Molecular Function | oxygen evolving activity | |
Biological Process | photosynthetic electron transport in photosystem II | |
Biological Process | response to herbicide |
Keywords
- Molecular function
- Biological process
- Ligand
Enzyme and pathway databases
Names & Taxonomy
Protein names
- Recommended namePhotosystem II protein D1
- EC number
- Short namesPSII D1 protein
- Alternative names
Gene names
Encoded on
- Chloroplast
Organism names
- Taxonomic lineageEukaryota > Viridiplantae > Streptophyta > Embryophyta > Tracheophyta > Lycopodiopsida > Lycopodiales > Lycopodiaceae > Huperzioideae > Huperzia
Accessions
- Primary accessionQ5SCW8
Subcellular Location
UniProt Annotation
GO Annotation
Plastid, chloroplast thylakoid membrane ; Multi-pass membrane protein
Features
Showing features for transmembrane.
Type | ID | Position(s) | Description | ||
---|---|---|---|---|---|
Transmembrane | 29-46 | Helical | |||
Transmembrane | 118-133 | Helical | |||
Transmembrane | 142-156 | Helical | |||
Transmembrane | 197-218 | Helical | |||
Transmembrane | 274-288 | Helical | |||
Keywords
- Cellular component
PTM/Processing
Features
Showing features for initiator methionine, modified residue, chain, propeptide.
Type | ID | Position(s) | Description | ||
---|---|---|---|---|---|
Initiator methionine | 1 | Removed | |||
Modified residue | 2 | N-acetylthreonine | |||
Modified residue | 2 | Phosphothreonine | |||
Chain | PRO_0000339999 | 2-344 | Photosystem II protein D1 | ||
Propeptide | PRO_0000340000 | 345-353 | |||
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
- PTM
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
Sequence
- Sequence statusComplete
- Sequence processingThe displayed sequence is further processed into a mature form.
- Length353
- Mass (Da)38,735
- Last updated2004-12-21 v1
- ChecksumE63DAE08F69DC97F
Sequence databases
Nucleotide Sequence | Protein Sequence | Molecule Type | Status | |
---|---|---|---|---|
AY660566 EMBL· GenBank· DDBJ | AAT80732.1 EMBL· GenBank· DDBJ | Genomic DNA |