Summary: Photosystem II reaction centre T protein
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Photosystem II reaction centre T protein Provide feedback
The exact function of this protein is unknown. It probably consists of a single transmembrane spanning helix. The P37256 protein, appears to be (i) a novel photosystem II subunit and (ii) required for maintaining optimal photosystem II activity under adverse growth conditions .
Monod C, Takahashi Y, Goldschmidt-Clermont M, Rochaix JD; , EMBO J 1994;13:2747-2754.: The chloroplast ycf8 open reading frame encodes a photosystem II polypeptide which maintains photosynthetic activity under adverse growth conditions. PUBMED:8026459 EPMC:8026459
External database links
This tab holds annotation information from the InterPro database.
InterPro entry IPR001743
Oxygenic photosynthesis uses two multi-subunit photosystems (I and II) located in the cell membranes of cyanobacteria and in the thylakoid membranes of chloroplasts in plants and algae. Photosystem II (PSII) has a P680 reaction centre containing chlorophyll 'a' that uses light energy to carry out the oxidation (splitting) of water molecules, and to produce ATP via a proton pump. Photosystem I (PSI) has a P700 reaction centre containing chlorophyll that takes the electron and associated hydrogen donated from PSII to reduce NADP+ to NADPH. Both ATP and NADPH are subsequently used in the light-independent reactions to convert carbon dioxide to glucose using the hydrogen atom extracted from water by PSII, releasing oxygen as a by-product.
PSII is a multisubunit protein-pigment complex containing polypeptides both intrinsic and extrinsic to the photosynthetic membrane [PUBMED:12518057, PUBMED:15100025]. Within the core of the complex, the chlorophyll and beta-carotene pigments are mainly bound to the antenna proteins CP43 (PsbC) and CP47 (PsbB), which pass the excitation energy on to the reaction centre proteins D1 (Qb, PsbA) and D2 (Qa, PsbD) that bind all the redox-active cofactors involved in the energy conversion process. The PSII oxygen-evolving complex (OEC) oxidises water to provide protons for use by PSI, and consists of OEE1 (PsbO), OEE2 (PsbP) and OEE3 (PsbQ). The remaining subunits in PSII are of low molecular weight (less than 10 kDa), and are involved in PSII assembly, stabilisation, dimerisation, and photo-protection [PUBMED:14871485].
This family represents the low molecular weight transmembrane protein PsbT found in PSII, which is thought to be associated with the D1 (PsbA) - D2 (PsbD) heterodimer. PsbT may be involved in the formation and/or stabilisation of dimeric PSII complexes, because in the absence of this protein dimeric PSII complexes were found to be less abundant. Furthermore, although PsbT does not confer photo-protection, it is required for the efficient recovery of photo-damaged PSII [PUBMED:11451956].
The mapping between Pfam and Gene Ontology is provided by InterPro. If you use this data please cite InterPro.
|Cellular component||membrane (GO:0016020)|
|photosystem II reaction center (GO:0009539)|
|photosystem II (GO:0009523)|
|Biological process||photosynthesis (GO:0015979)|
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|Seed source:||Pfam-B_1880 (release 3.0)|
|Number in seed:||3|
|Number in full:||1892|
|Average length of the domain:||27.70 aa|
|Average identity of full alignment:||90 %|
|Average coverage of the sequence by the domain:||83.23 %|
|HMM build commands:||
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 23193494 -E 1000 --cpu 4 HMM pfamseq
|Family (HMM) version:||12|
|Download:||download the raw HMM for this family|
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For those sequences which have a structure in the Protein DataBank, we use the mapping between UniProt, PDB and Pfam coordinate systems from the PDBe group, to allow us to map Pfam domains onto UniProt sequences and three-dimensional protein structures. The table below shows the structures on which the PsbT domain has been found. There are 17 instances of this domain found in the PDB. Note that there may be multiple copies of the domain in a single PDB structure, since many structures contain multiple copies of the same protein seqence.
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