Summary: Cytochrome b559, alpha (gene psbE) and beta (gene psbF)subunits
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|Cytochrome b559, alpha (gene psbE) and beta (gene psbF)subunits|
Structure of Photosystem II from Thermosynechococcus elongatus.
|Lumenal portion of Cytochrome b559, alpha (gene psbE) subunit|
Structure of oxygen-evolving photosystem II from Thermosynechococcus vulcanus.
Cytochrome b559 is an important component of Photosystem II.
PSII is a multisubunit protein-pigment complex containing polypeptides both intrinsic and extrinsic to the photosynthetic membrane. 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 chlorophylls in 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) provides electrons to re-reduce the PSII reaction center and oxidizes 2 water molecules to recover its reduced initial state. It 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.
Cytochrome b559, which forms part of the reaction centre core of PSII is a heterodimer composed of one alpha subunit (PsbE), one beta (PsbF) subunit, and a heme cofactor. Two histidine residues from each subunit coordinate the haem. Although cytochrome b559 is a redox-active protein, it is unlikely to be involved in the primary electron transport in PSII due to its very slow photo-oxidation and photo-reduction kinetics. Instead, cytochrome b559 could participate in a secondary electron transport pathway that helps protect PSII from photo-damage. Cytochrome b559 is essential for PSII assembly.
This domain occurs in both the alpha and beta subunits of cytochrome B559. In the alpha sbunit it occurs together with a lumenal domain (InterPro: IPR013082), while in the beta subunit it occurs on its own.
Cytochrome b559 can exist in three forms, each with a characteristic redox potential, These forms are very low potential (VLP), ≤ zero mV; low potential (LP) at 60 mV; and high potential (HP) at 370 mV. There is also an intermediate potential (IP) form that has a redox potential at pH 6.5-7.0 that ranges from 170 to 240 mV. In oxygen evolving reaction centers, more than half of the cyt b559 is in the HP form. In manganese depleted non oxygen evolving photosystem II reaction centers, cyt b559 is usually in the LP form.
- Loll B, Kern J, Saenger W, Zouni A, Biesiadka J (December 2005). "Towards complete cofactor arrangement in the 3.0 A resolution structure of photosystem II". Nature. 438 (7070): 1040–4. doi:10.1038/nature04224. PMID 16355230.
- Kamiya N, Shen JR (January 2003). "Crystal structure of oxygen-evolving photosystem II from Thermosynechococcus vulcanus at 3.7-A resolution". Proc. Natl. Acad. Sci. U.S.A. 100 (1): 98–103. doi:10.1073/pnas.0135651100. PMC . PMID 12518057.
- Kamiya N, Shen JR (2003). "Crystal structure of oxygen-evolving photosystem II from Thermosynechococcus vulcanus at 3.7-A resolution". Proc. Natl. Acad. Sci. U.S.A. 100 (1): 98–103. doi:10.1073/pnas.0135651100. PMC . PMID 12518057.
- Blankenship RE, Raymond J (2004). "The evolutionary development of the protein complement of photosystem 2". Biochimica et Biophysica Acta (BBA) - Bioenergetics. 1655 (1-3): 133–139. doi:10.1016/j.bbabio.2003.10.015. PMID 15100025.
- Schroder WP, Shi LX (2004). "The low molecular mass subunits of the photosynthetic supracomplex, photosystem II". Biochimica et Biophysica Acta (BBA) - Bioenergetics. 1608 (2-3): 75–96. doi:10.1016/j.bbabio.2003.12.004. PMID 14871485.
- Burda K, Kruk J, Borgstadt R, Stanek J, StrzaBka K, Schmid GH, Kruse O (2003). "Mössbauer studies of the non-heme iron and cytochrome b559 in a Chlamydomonas reinhardtii PSI- mutant and their interactions with alpha-tocopherol quinone". FEBS Lett. 535 (1-3): 159–165. doi:10.1016/S0014-5793(02)03895-4. PMID 12560096.
- Mizusawa N, Yamashita T, Miyao M (1999). "Restoration of the high-potential form of cytochrome b559 of photosystem II occurs via a two-step mechanism under illumination in the presence of manganese ions". Biochimica et Biophysica Acta (BBA) - Bioenergetics. 1410 (3): 273–286. doi:10.1016/S0005-2728(99)00005-5. PMID 10082793.
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Cytochrome b559, alpha (gene psbE) and beta (gene psbF)subunits Provide feedback
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External database links
This tab holds annotation information from the InterPro database.
InterPro entry IPR013081
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].
Cytochrome b559, which forms part of the reaction centre core of PSII is a heterodimer composed of one alpha subunit (PsbE), one beta (PsbF) subunit, and a haem cofactor. Two histidine residues from each subunit coordinate the haem. Although cytochrome b559 is a redox-active protein, it is unlikely to be involved in the primary electron transport in PSII due to its very slow photo-oxidation and photo-reduction kinetics. Instead, cytochrome b559 could participate in a secondary electron transport pathway that helps protect PSII from photo-damage. Cytochrome b559 is essential for PSII assembly [PUBMED:12560096].
This domain occurs in both the alpha and beta subunits of cytochrome B559. In the alpha subunit it occurs together with a lumenal domain (INTERPRO), while in the beta subunit it occurs on its own.
The mapping between Pfam and Gene Ontology is provided by InterPro. If you use this data please cite InterPro.
|Biological process||photosynthesis (GO:0015979)|
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1Cannot generate PP/Heatmap alignments for seeds; no PP data available
Key: available, not generated, — not available.
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|Number in seed:||16|
|Number in full:||487|
|Average length of the domain:||28.80 aa|
|Average identity of full alignment:||51 %|
|Average coverage of the sequence by the domain:||41.13 %|
|HMM build commands:||
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 45638612 -E 1000 --cpu 4 HMM pfamseq
|Family (HMM) version:||19|
|Download:||download the raw HMM for this family|
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The tree is built by looking at each sequence in the full alignment for the family. We take the name of the species given by UniProt and try to map that to the full taxonomic tree from NCBI. In some cases, the name chosen by UniProt does not map to any node in the NCBI tree, perhaps because the chosen name is listed as a synonym or a misspelling in the NCBI taxonomy.
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There are 12 interactions for this family. More...
We determine these interactions using iPfam, which considers the interactions between residues in three-dimensional protein structures and maps those interactions back to Pfam families. You can find more information about the iPfam algorithm in the journal article that accompanies the website.
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 Cytochrom_B559 domain has been found. There are 170 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 sequence.
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