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87  structures 28  species 0  interactions 147  sequences 2  architectures

Family: Toxin_3 (PF00537)

Summary: Scorpion toxin-like domain

Pfam includes annotations and additional family information from a range of different sources. These sources can be accessed via the tabs below.

This is the Wikipedia entry entitled "Scorpion toxin". More...

Scorpion toxin Edit Wikipedia article

Scorpion toxin-like domain
Identifiers
SymbolToxin_3
PfamPF00537
InterProIPR002061
SCOP22sn3 / SCOPe / SUPFAM
OPM superfamily61
OPM protein1djt

Scorpion toxins are proteins, which may be mammal or insect specific, bind to sodium channels, inhibiting the inactivation of activated channels and blocking neuronal transmission. The complete covalent structure of the toxins has been deduced: it comprises around 66 amino acid residues and is cross- linked by 4 disulphide bridges[1][2]. An anti-epilepsy peptide isolated from scorpion venom[3] shows similarity to both scorpion neurotoxins and anti-insect toxins.

This family also contains a group of proteinase inhibitors from Arabidopsis thaliana and Brassica spp., which belong to MEROPS inhibitor family I18, clan I-. The Brassica napus (Oil seed rape) and Sinapis alba (White mustard) inhibitors[4][5], inhibit the catalytic activity of bovine beta-trypsin and bovine alpha-chymotrypsin, which belong to MEROPS peptidase family S1 (InterPro: IPR001254)[6].

This family contains both neurotoxins and plant defensins. The mustard trypsin inhibitor, MTI-2, is plant defensin. It is a potent inhibitor of trypsin with no activity towards chymotrypsin. MTI-2 is toxic for Lepidopteran insects, but has low activity against aphids. Brazzein is plant defensin-like protein. It is pH-stable, heat-stable and intensely sweet protein [7]

Subfamilies

References

  1. ^ Granier C, Kopeyan C, Rochat H, Mansuelle P, Sampieri F, Brando T, Bahraoui EM (1990). "Primary structure of scorpion anti-insect toxins isolated from the venom of Leiurus quinquestriatus quinquestriatus". FEBS Lett. 261 (2): 423–426. PMID 2311768.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  2. ^ Rochat H, Gregoire J (1983). "Covalent structure of toxins I and II from the scorpion Buthus occitanus tunetanus". Toxicon. 21 (1): 153–162. PMID 6845379.
  3. ^ Zhou XH, Yang D, Zhang JH, Liu CM, Lei KJ (1989). "Purification and N-terminal partial sequence of anti-epilepsy peptide from venom of the scorpion Buthus martensii Karsch". Biochem. J. 257 (2): 509–517. PMID 2930463.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  4. ^ Ronchi S, Ceciliani F, Ascenzi P, Bortolotti F, Menegatti E, Palmieri S (1994). "Purification, inhibitory properties, amino acid sequence and identification of the reactive site of a new serine proteinase inhibitor from oil-rape (Brassica napus) seed". FEBS Lett. 342 (2): 221–224. PMID 8143882.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  5. ^ Bolognesi M, Ronchi S, Tedeschi G, Ascenzi P, Bortolotti F, Menegatti E, Palmieri S, Thomas RM (1992). "Purification, inhibitory properties and amino acid sequence of a new serine proteinase inhibitor from white mustard (Sinapis alba L.) seed". FEBS Lett. 301 (1): 10-1 4. PMID 1451776. {{cite journal}}: line feed character in |pages= at position 5 (help)CS1 maint: multiple names: authors list (link)
  6. ^ Rawlings ND, Barrett AJ, Tolle DP (2004). "Evolutionary families of peptidase inhibitors". Biochem. J. 378: -. PMID 14705960.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  7. ^ Sweetness determinant sites of brazzein, a small, heat-stable, sweet-tasting protein. Assa di-Porter FM, Aceti DJ, Markley JL; Arch Biochem Biophys 2000;376:259-265. PMID 10775411
This article incorporates text from the public domain Pfam and InterPro: IPR002061

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.

Scorpion toxin-like domain Provide feedback

This family contains both neurotoxins and plant defensins. The mustard trypsin inhibitor, MTI-2, is plant defensin. It is a potent inhibitor of trypsin with no activity towards chymotrypsin. MTI-2 is toxic for Lepidopteran insects, but has low activity against aphids [1]. Brazzein is plant defensin-like protein. It is pH-stable, heat-stable and intensely sweet protein [2]. The scorpion toxin (a neurotoxin) binds to sodium channels and inhibits the activation mechanisms of the channels, thereby blocking neuronal transmission. Scorpion toxins bind to sodium channels and inhibit the activation mechanisms of the channels, thereby blocking neuronal transmission

Literature references

  1. Ceci LR, Volpicella M, Rahbe Y, Gallerani R, Beekwilder J, Jongsma MA; , Plant J 2003;33:557-566.: Selection by phage display of a variant mustard trypsin inhibitor toxic against aphids. PUBMED:12581313 EPMC:12581313

  2. Assadi-Porter FM, Aceti DJ, Markley JL; , Arch Biochem Biophys 2000;376:259-265.: Sweetness determinant sites of brazzein, a small, heat-stable, sweet-tasting protein. PUBMED:10775411 EPMC:10775411


Internal database links

External database links

This tab holds annotation information from the InterPro database.

InterPro entry IPR002061

This family contains both neurotoxins and plant defensins. The mustard trypsin inhibitor, MTI-2, is a plant defensin. It is a potent inhibitor of trypsin with no activity towards chymotrypsin. MTI-2 is toxic for Lepidopteran insects, but has low activity against aphids [ PUBMED:12581313 ]. The scorpion toxin (a neurotoxin) binds to sodium channels and inhibits the activation mechanisms of the channels, thereby blocking neuronal transmission.

Gene Ontology

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Domain organisation

Below is a listing of the unique domain organisations or architectures in which this domain is found. More...

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Pfam Clan

This family is a member of clan Knottin_1 (CL0054), which has the following description:

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 15 members:

BmKX Defensin_2 Defensin_5 Defensin_like Gamma-thionin Macin SCRL SLR1-BP Toxin_17 Toxin_2 Toxin_3 Toxin_37 Toxin_38 Toxin_5 Toxin_6

Alignments

We store a range of different sequence alignments for families. As well as the seed alignment from which the family is built, we provide the full alignment, generated by searching the sequence database (reference proteomes) using the family HMM. We also generate alignments using four representative proteomes (RP) sets and the UniProtKB sequence database. More...

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We make a range of alignments for each Pfam-A family. You can see a description of each above. You can view these alignments in various ways but please note that some types of alignment are never generated while others may not be available for all families, most commonly because the alignments are too large to handle.

  Seed
(33)
Full
(147)
Representative proteomes UniProt
(950)
RP15
(20)
RP35
(27)
RP55
(102)
RP75
(159)
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PP/heatmap 1 View           

1Cannot generate PP/Heatmap alignments for seeds; no PP data available

Key: ✓ available, x not generated, not available.

Format an alignment

  Seed
(33)
Full
(147)
Representative proteomes UniProt
(950)
RP15
(20)
RP35
(27)
RP55
(102)
RP75
(159)
Alignment:
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We make all of our alignments available in Stockholm format. You can download them here as raw, plain text files or as gzip-compressed files.

  Seed
(33)
Full
(147)
Representative proteomes UniProt
(950)
RP15
(20)
RP35
(27)
RP55
(102)
RP75
(159)
Raw Stockholm Download   Download   Download   Download   Download   Download   Download  
Gzipped Download   Download   Download   Download   Download   Download   Download  

You can also download a FASTA format file containing the full-length sequences for all sequences in the full alignment.

HMM logo

HMM logos is one way of visualising profile HMMs. Logos provide a quick overview of the properties of an HMM in a graphical form. You can see a more detailed description of HMM logos and find out how you can interpret them here. More...

Trees

This page displays the phylogenetic tree for this family's seed alignment. We use FastTree to calculate neighbour join trees with a local bootstrap based on 100 resamples (shown next to the tree nodes). FastTree calculates approximately-maximum-likelihood phylogenetic trees from our seed alignment.

Note: You can also download the data file for the tree.

Curation and family details

This section shows the detailed information about the Pfam family. You can see the definitions of many of the terms in this section in the glossary and a fuller explanation of the scoring system that we use in the scores section of the help pages.

Curation View help on the curation process

Seed source: Pfam-B_8170 (release 8.0)
Previous IDs: toxin_3; Toxin_3; Toxin3_;
Type: Domain
Sequence Ontology: SO:0000417
Author: Bateman A , Moxon SJ , Finn RD
Number in seed: 33
Number in full: 147
Average length of the domain: 59 aa
Average identity of full alignment: 42 %
Average coverage of the sequence by the domain: 62.55 %

HMM information View help on HMM parameters

HMM build commands:
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 61295632 -E 1000 --cpu 4 HMM pfamseq
Model details:
Parameter Sequence Domain
Gathering cut-off 21.5 21.5
Trusted cut-off 21.5 21.6
Noise cut-off 21.4 21.4
Model length: 55
Family (HMM) version: 21
Download: download the raw HMM for this family

Species distribution

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Structures

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_3 domain has been found. There are 87 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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AlphaFold Structure Predictions

The list of proteins below match this family and have AlphaFold predicted structures. Click on the protein accession to view the predicted structure.

Protein Predicted structure External Information
O22866 View 3D Structure Click here
O22867 View 3D Structure Click here
O22869 View 3D Structure Click here
Q2V3S0 View 3D Structure Click here
Q42328 View 3D Structure Click here
Q42330 View 3D Structure Click here
Q8RYE7 View 3D Structure Click here