B2XT21 · PSBD_HETA2
- ProteinPhotosystem II D2 protein
- GenepsbD1; psbD2
- StatusUniProtKB reviewed (Swiss-Prot)
- Amino acids351 (go to sequence)
- Protein existenceInferred from homology
- Annotation score3/5
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. D2 is needed for assembly of a stable PSII complex.
Miscellaneous
2 of the reaction center chlorophylls (ChlD1 and ChlD2) are entirely coordinated by water.
Catalytic activity
- 2 a plastoquinone + 2 H2O + 4 hnu = 2 a plastoquinol + O2
2 a plastoquinone RHEA-COMP:9562 + 2 CHEBI:15377 + 4 CHEBI:30212 = 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. 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.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Binding site | 116 | Mg (UniProtKB | ChEBI) of chlorophyll a ChlzD2 (UniProtKB | ChEBI); axial binding residue | ||||
Sequence: H | ||||||
Binding site | 128 | pheophytin a D2 (UniProtKB | ChEBI) | ||||
Sequence: Q | ||||||
Binding site | 141 | pheophytin a D2 (UniProtKB | ChEBI) | ||||
Sequence: N | ||||||
Binding site | 196 | Mg (UniProtKB | ChEBI) of chlorophyll a PD2 (UniProtKB | ChEBI); axial binding residue | ||||
Sequence: H | ||||||
Binding site | 213 | a plastoquinone Q(A) (UniProtKB | ChEBI) | ||||
Sequence: H | ||||||
Binding site | 213 | Fe cation (UniProtKB | ChEBI); ligand shared with heterodimeric partner | ||||
Sequence: H | ||||||
Binding site | 260 | a plastoquinone Q(A) (UniProtKB | ChEBI) | ||||
Sequence: F | ||||||
Binding site | 267 | Fe cation (UniProtKB | ChEBI); ligand shared with heterodimeric partner | ||||
Sequence: H |
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 | |
Biological Process | photosynthetic electron transport in photosystem II |
Keywords
- Molecular function
- Biological process
- Ligand
Enzyme and pathway databases
Names & Taxonomy
Protein names
- Recommended namePhotosystem II D2 protein
- EC number
- Short namesPSII D2 protein
- Alternative names
Gene names
Encoded on
- Chloroplast
Organism names
- Strain
- Taxonomic lineageEukaryota > Sar > Stramenopiles > Ochrophyta > Raphidophyceae > Chattonellales > Chattonellaceae > Heterosigma
Accessions
- Primary accessionB2XT21
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 | 39-59 | Helical | ||||
Sequence: TAYLAVGGWFTGTTFVTSWYT | ||||||
Transmembrane | 123-139 | Helical | ||||
Sequence: GFCLRQFEIARLVGIRP | ||||||
Transmembrane | 151-164 | Helical | ||||
Sequence: IFVSVFLLYPLGQA | ||||||
Transmembrane | 206-226 | Helical | ||||
Sequence: GALLCAIHGATVENTLFEDGD | ||||||
Transmembrane | 277-293 | Helical | ||||
Sequence: GLWTSAIGIVGLALNLR |
Keywords
- Cellular component
PTM/Processing
Features
Showing features for chain.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Chain | PRO_0000359707 | 1-351 | Photosystem II D2 protein | |||
Sequence: MTIAIGQNQERGVFDLVDDWLKRDRFVFVGWSGLLLFPTAYLAVGGWFTGTTFVTSWYTHGLASSYLEGCNFLTAAVSTPANSMGHSLILLWGPEAQGDFTRWCQIGGLWTFVALHGAFGLIGFCLRQFEIARLVGIRPYNAIAFSGPISIFVSVFLLYPLGQASWFFAPSFGVAAIFRFLLFLQGFHNWTLNPFHMMGVAGILGGALLCAIHGATVENTLFEDGDAANTFRAFTPTQSEETYSMVTANRFWSQIFGVAFSNKRWLHFFMLFVPVTGLWTSAIGIVGLALNLRAYDFVSQELRAAEDPEFETFYTKNILLNEGIRAWMAAQDQPHENFVFPEEVLPRGNAL |
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
- Length351
- Mass (Da)39,122
- Last updated2008-07-01 v1
- Checksum356DAC569B034598
Sequence databases
Nucleotide Sequence | Protein Sequence | Molecule Type | Status | |
---|---|---|---|---|
EU168190 EMBL· GenBank· DDBJ | ABV65919.1 EMBL· GenBank· DDBJ | Genomic DNA | ||
EU168190 EMBL· GenBank· DDBJ | ABV65963.1 EMBL· GenBank· DDBJ | Genomic DNA |