Summary: Scorpion toxin-like domain
This is the Wikipedia entry entitled "Scorpion toxin". More...
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Scorpion toxin Edit Wikipedia article
|Scorpion long-chain toxin|
Crystal structure of toxin II from the scorpion Androctonus australis Hector.
|Scorpion short toxin|
Scorpion toxins are proteins found in the venom of scorpions. Their toxic effect may be mammal or insect specific, and acts by binding to sodium channels, inhibiting the inactivation of activated channels and blocking neuronal transmission.
The Brassica napus (Oil seed rape) and Sinapis alba (White mustard) inhibitors, inhibit the catalytic activity of bovine beta-trypsin and bovine alpha-chymotrypsin, which belong to MEROPS peptidase family S1 (IPR001254).
This group of proteins is now used in the creation of insecticides, vaccines, and protein engineering scaffolds.
The complete covalent structure of several such toxins has been deduced: They comprise around 66 amino acid residues forming a three stranded anti-parallel beta sheet over which lies an alpha helix of approximately three turns. Four disulfide bridges cross-link the structure of the long-chain toxins whereas the short toxins contain only three. BmKAEP, an anti-epilepsy peptide isolated from the venom of the Manchurian scorpion, shows similarity to both scorpion neurotoxins and anti-insect toxins.
The toxin's molecular function is to inhibit ion channels. Scorpion toxins are used in insecticides, vaccines, and protein engineering scaffolds. The toxins are now used to treat cancer patients by injecting fluorescent scorpion toxin into cancerous tissue to show tumor boundaries. Scorpion toxin genes are also used to kill insect pests by creating hypervirulent fungus in the insect through gene insertion.
- PDB 1PTX; Housset D, Habersetzer-Rochat C, Astier JP, Fontecilla-Camps JC (April 1994). "Crystal structure of toxin II from the scorpion Androctonus australis Hector refined at 1.3 A resolution". J. Mol. Biol. 238 (1): 88–103. doi:10.1006/jmbi.1994.1270. PMID 8145259.
- Krezel, A. M.; Kasibhatla, C.; Hidalgo, P.; MacKinnon, R.; Wagner, G. (1995). "Solution structure of the potassium channel inhibitor agitoxin 2: Caliper for probing channel geometry". Protein Science 4 (8): 1478–1489. doi:10.1002/pro.5560040805. PMC 2143198. PMID 8520473.
- 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. doi:10.1016/0014-5793(94)80505-9. PMID 8143882.
- 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): 10–14. doi:10.1016/0014-5793(92)80199-Q. PMID 1451776.
- Rawlings ND, Barrett AJ, Tolle DP (2004). "Evolutionary families of peptidase inhibitors". Biochem. J. 378 (Pt 3): 705–16. doi:10.1042/BJ20031825. PMC 1224039. PMID 14705960.
- 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. doi:10.1016/0014-5793(90)80607-K. PMID 2311768.
- Rochat H, Gregoire J (1983). "Covalent structure of toxins I and II from the scorpion Buthus occitanus tunetanus". Toxicon 21 (1): 153–162. doi:10.1016/0041-0101(83)90058-2. PMID 6845379.
- 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. PMC 1135608. PMID 2930463.
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 . Brazzein is plant defensin-like protein. It is pH-stable, heat-stable and intensely sweet protein . 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
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
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:2581313]. Brazzein is a plant defensin-like protein. It is pH-stable, heat-stable and intensely sweet protein [PUBMED:10775411]. The scorpion toxin (a neurotoxin) binds to sodium channels and inhibits the activation mechanisms of the channels, thereby blocking neuronal transmission.
The mapping between Pfam and Gene Ontology is provided by InterPro. If you use this data please cite InterPro.
|Cellular component||extracellular region (GO:0005576)|
|Molecular function||ion channel inhibitor activity (GO:0008200)|
- the number of sequences which exhibit this architecture
a textual description of the architecture, e.g. Gla, EGF x 2, Trypsin.
This example describes an architecture with one
Gladomain, followed by two consecutive
EGFdomains, and finally a single
- the UniProt description of the protein sequence
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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 11 members:Defensin_2 DUF2667 Gamma-thionin SCRL SLR1-BP Toxin_17 Toxin_2 Toxin_3 Toxin_37 Toxin_38 Toxin_5
We make a range of alignments for each Pfam-A family:
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Curation and family details
|Seed source:||Pfam-B_8170 (release 8.0)|
|Author:||Bateman A, Moxon SJ, Finn RD|
|Number in seed:||33|
|Number in full:||487|
|Average length of the domain:||53.00 aa|
|Average identity of full alignment:||38 %|
|Average coverage of the sequence by the domain:||69.05 %|
|HMM build commands:||
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 23193494 -E 1000 --cpu 4 HMM pfamseq
|Family (HMM) version:||13|
|Download:||download the raw HMM for this family|
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There is 1 interaction 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 Toxin_3 domain has been found. There are 78 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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