Summary: Ergtoxin family
Ergtoxin family Provide feedback
This family consists of ergtoxin peptides which are toxins secreted by the scorpions. The ergtoxins are capable of blocking the function of K+ channels. More than 100 ergtoxins have been found from scorpion venoms and they have been classified into three subfamilies according to their primary structures .
Frenal K, Xu CQ, Wolff N, Wecker K, Gurrola GB, Zhu SY, Chi CW, Possani LD, Tytgat J, Delepierre M; , Proteins 2004;56:367-375.: Exploring structural features of the interaction between the scorpion toxinCnErg1 and ERG K+ channels. PUBMED:15211519 EPMC:15211519
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This tab holds annotation information from the InterPro database.
InterPro entry IPR012622
The Ergtoxin (ErgTx) family is a class of peptides from scorpion venom that specifically block ERG (ether-a-go-go-related gene) K+ channels of the nerve, heart and endocrine cells [PUBMED:11023354, PUBMED:12650941, PUBMED:12459475].
Peptides of the ErgTx family have from 42 to 47 amino acid residues cross-linked by four disulphide bridges. The four disulphide bridges have been assigned as C1-C4, C2-C6, C3-C7 and C5-C8 (see the schematic representation below) [PUBMED:11023354]. ErgTxs consist of a triple-stranded beta-sheet and an alpha-helix, as is typical of K+ channel scorpion toxins. There is a large hydrophobic patch on the surface of the toxin, surrounding a central lysine residue located near the beta-hairpin loop between the second and third strands of the beta-sheet. It has been postulated that this hydrophobic patch is likely to form part of the binding surface of the toxin [PUBMED:12650941]. Peptides of the ErgTx family possess a Knottin scaffold (see http://knottin.cbs.cnrs.fr).
Some proteins known to belong to the ErgTx family are listed below:
- ErgTx1, ErgTx2 and ErgTx3 from Centruroides elegans (Bark scorpion).
- ErgTx1, ErgTx2, ErgTx3 and ErgTx4 from Centruroides exilicauda (Bark scorpion).
- ErgTx1, ErgTx2 and ErgTx3 from Centruroides gracilis (Slenderbrown scorpion) (Florida bark scorpion).
- ErgTx1, ErgTx2, ErgTx3 and ErgTx4 from Centruroides limpidus limpidus (Mexican scorpion).
- ErgTx1, ErgTx2, ErgTx3, ErgTx4, ErgTx5 and gamma-KTx 4.12 from Centruroides sculpturatus (Bark scorpion).
- ErgTx, ErgTx2, ErgTx3, ErgTx4 and ErgTx5 from Centruroides noxius (Mexican scorpion).
|Cellular component||extracellular region (GO:0005576)|
|Molecular function||potassium channel inhibitor activity (GO:0019870)|
|Biological process||pathogenesis (GO:0009405)|
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This clan includes a number of toxin families that share the knottin structure. These families come from scorpions, plants and arthropods.
The clan contains the following 12 members:Defensin_2 DUF2667 Gamma-thionin SCRL SLR1-BP Toxin_17 Toxin_2 Toxin_3 Toxin_37 Toxin_38 Toxin_5 Toxin_6
We make a range of alignments for each Pfam-A family:
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Curation and family details
|Seed source:||Short protein clustering|
|Previous IDs:||Toxin_17; Toxin_17_;|
|Number in seed:||4|
|Number in full:||27|
|Average length of the domain:||41.00 aa|
|Average identity of full alignment:||79 %|
|Average coverage of the sequence by the domain:||93.81 %|
|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:||7|
|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 Toxin_17 domain has been found. There are 2 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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