Summary: PsbL protein
PsbL protein Provide feedback
This family consists of the photosystem II reaction centre protein PsbJ from plants and Cyanobacteria. The function of this small protein is unknown. Interestingly the mRNA for this protein requires a post-transcriptional modification of an ACG triplet to form an AUG initiator codon [1,2].
Kuntz M, Camara B, Weil JH, Schantz R; , Plant Mol Biol 1992;20:1185-1188.: The psbL gene from bell pepper (Capsicum annuum): plastid RNA editing also occurs in non-photosynthetic chromoplasts. PUBMED:1463853 EPMC:1463853
Kudla J, Igloi GL, Metzlaff M, Hagemann R, Kossel H; , EMBO J 1992;11:1099-1103.: RNA editing in tobacco chloroplasts leads to the formation of a translatable psbL mRNA by a C to U substitution within the initiation codon. PUBMED:1547774 EPMC:1547774
External database links
This tab holds annotation information from the InterPro database.
InterPro entry IPR003372
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 PsbL found in PSII. PsbL is located in a gene cluster with PsbE, PsbF and PsbJ (PsbEFJL). Both PsbL and PsbJ (INTERPRO) are essential for proper assembly of the OEC. Mutations in PsbL prevent the formation of both PSII core dimers and PSII-light harvesting complex [PUBMED:14686923]. In addition, both PsbL and PsbJ are involved in the unidirectional flow of electrons, where PsbJ regulates the forward electron flow from D2 (Qa) to the plastoquinone pool, and PsbL prevents the reduction of PSII by back electron flow from plastoquinol protecting PSII from photo-inactivation [PUBMED:14979726].
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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Curation and family details
|Seed source:||Pfam-B_1884 (release 5.4)|
|Number in seed:||7|
|Number in full:||1456|
|Average length of the domain:||36.70 aa|
|Average identity of full alignment:||90 %|
|Average coverage of the sequence by the domain:||94.79 %|
|HMM build commands:||
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 80369284 -E 1000 --cpu 4 HMM pfamseq
|Family (HMM) version:||13|
|Download:||download the raw HMM for this family|
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There are 15 interactions for this family. More...
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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 PsbL domain has been found. There are 37 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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