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11  structures 1024  species 4  interactions 1072  sequences 2  architectures

Family: PSI_8 (PF00796)

Summary: Photosystem I reaction centre subunit VIII

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This is the Wikipedia entry entitled "Sea anemone neurotoxin". More...

Sea anemone neurotoxin Edit Wikipedia article

Anemone neurotoxin
PDB 1atx EBI.jpg
Structure of the neurotoxin ATX Ia from Anemonia sulcata.[1]
Symbol Toxin_4
Pfam PF00706
Pfam clan CL0075
InterPro IPR000693
SCOP 1atx
OPM superfamily 56
OPM protein 1apf
Antihypertensive protein BDS-I/II
PDB 1bds EBI.jpg
Structure of the antihypertensive and antiviral protein BDS-I from the sea anemone Anemonia sulcata.[2]
Symbol BDS_I_II
Pfam PF07936
Pfam clan CL0075
InterPro IPR012414
SCOP 2bds
OPM superfamily 56
OPM protein 1bds

Sea anemone neurotoxin is the name given to neurotoxins produced by sea anemones with related structure and function. A number of proteins belong to this family, including calitoxin and anthopleurin. The neurotoxins bind specifically to the sodium channel, thereby delaying its inactivation during signal transduction, resulting in strong stimulation of mammalian cardiac muscle contraction. Calitoxin 1 has been found in neuromuscular preparations of crustaceans, where it increases transmitter release, causing firing of the axons. Three disulfide bonds are present in this protein.[3][4][5]

This family also includes the antihypertensive and antiviral proteins BDS-I (P11494) and BDS-II (P59084) expressed by Anemonia sulcata. BDS-I is organised into a triple-stranded antiparallel beta-sheet, with an additional small antiparallel beta-sheet at the N-terminus.[6] Both peptides are known to specifically block the Kv3.4 potassium channel, and thus bring about a decrease in blood pressure.[7] Moreover, they inhibit the cytopathic effects of mouse hepatitis virus strain MHV-A59 on mouse liver cells, by an unknown mechanism.[6]

See also


  1. ^ Widmer H, Billeter M, Wüthrich K (1989). "Three-dimensional structure of the neurotoxin ATX Ia from Anemonia sulcata in aqueous solution determined by nuclear magnetic resonance spectroscopy". Proteins 6 (4): 357–71. doi:10.1002/prot.340060403. PMID 2576133. 
  2. ^ Driscoll PC, Gronenborn AM, Beress L, Clore GM (March 1989). "Determination of the three-dimensional solution structure of the antihypertensive and antiviral protein BDS-I from the sea anemone Anemonia sulcata: a study using nuclear magnetic resonance and hybrid distance geometry-dynamical simulated annealing". Biochemistry 28 (5): 2188–98. doi:10.1021/bi00431a033. PMID 2566326. 
  3. ^ Norton TR (1981). "Cardiotonic polypeptides from Anthopleura xanthogrammica (Brandt) and A. elegantissima (Brandt)". Fed. Proc. 40 (1): 21–5. PMID 6108877. 
  4. ^ Yasunobu KT, Norton TR, Reimer NS, Yasunobu CL (1985). "Amino acid sequence of the Anthopleura xanthogrammica heart stimulant, anthopleurin-B". J. Biol. Chem. 260 (15): 8690–3. PMID 4019448. 
  5. ^ Scanlon MJ, Pallaghy PK, Norton RS, Monks SA (1995). "Solution structure of the cardiostimulant polypeptide anthopleurin-B and comparison with anthopleurin-A". Structure 3 (8): 791–803. doi:10.1016/s0969-2126(01)00214-3. PMID 7582896. 
  6. ^ a b Clore GM, Driscoll PC, Gronenborn AM, Beress L (1989). "Determination of the three-dimensional solution structure of the antihypertensive and antiviral protein BDS-I from the sea anemone Anemonia sulcata: a study using nuclear magnetic resonance and hybrid distance geometry-dynamical simulated annealing". Biochemistry 28 (5): 2188–2198. doi:10.1021/bi00431a033. PMID 2566326. 
  7. ^ Lazdunski M, Schweitz H, Diochot S, Beress L (1998). "Sea anemone peptides with a specific blocking activity against the fast inactivating potassium channel Kv3.4". J. Biol. Chem. 273 (12): 6744–6749. doi:10.1074/jbc.273.12.6744. PMID 9506974. 

This article incorporates text from the public domain Pfam and InterPro IPR000693

This page is based on a Wikipedia article. The text is available under the Creative Commons Attribution/Share-Alike License.

This tab holds the annotation information that is stored in the Pfam database. As we move to using Wikipedia as our main source of annotation, the contents of this tab will be gradually replaced by the Wikipedia tab.

Photosystem I reaction centre subunit VIII Provide feedback

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This tab holds annotation information from the InterPro database.

InterPro entry IPR001302

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.

This entry represents subunit VIII (PsaI) of the photosystem I (PSI) reaction centre. PSI is located, along with photosystem II (PSII), in the thylakoid photosynthetic membranes of plants, green algae and cyanobacteria. The crystal structure of PSI from the thermophilic cyanobacterium Synechococcus elongatus (Thermosynechococcus elongatus) has 12 protein subunits and 127 cofactors comprising 96 chlorophylls, 2 phylloquinones, 3 4Fe4S clusters, 22 carotenoids, 4 lipids, and a putative calcium ion [PUBMED:11418848]. PsaI consists of a single transmembrane helix, and has a crucial role in aiding normal structural organisation of PsaL within the PSI complex and the absence of PsaI alters PsaL organisation, leading to a small, but physiologically significant, defect in PSI function [PUBMED:7608190]. PsaL encodes a subunit of PSI and is necessary for trimerisation of PSI. PsaL may constitute the trimer-forming domain in the structure of PSI [PUBMED:8262256].

Gene Ontology

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Domain organisation

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Curation and family details

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Seed source: Pfam-B_528 (release 2.1)
Previous IDs: none
Type: Family
Author: Bateman A
Number in seed: 26
Number in full: 1072
Average length of the domain: 24.20 aa
Average identity of full alignment: 73 %
Average coverage of the sequence by the domain: 64.72 %

HMM information View help on HMM parameters

HMM build commands:
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 80369284 -E 1000 --cpu 4 HMM pfamseq
Model details:
Parameter Sequence Domain
Gathering cut-off 19.8 19.8
Trusted cut-off 20.9 20.7
Noise cut-off 19.5 19.5
Model length: 25
Family (HMM) version: 14
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Species distribution

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Archea Archea Eukaryota Eukaryota
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There are 4 interactions for this family. More...

PsaL PsaM PsaA_PsaB PSI_PsaH


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 PSI_8 domain has been found. There are 11 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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