Symbol Toxin_3 InterPro IPR002061 SUPERFAMILY 2sn3 | Pfam PF00537 SCOP 2sn3 OPM superfamily 61 | |
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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.
Contents
The family includes related short- and long-chain scorpion toxins. It also contains a group of proteinase inhibitors from the plants Arabidopsis thaliana and Brassica spp.
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 (InterPro: IPR001254).
This group of proteins is now used in the creation of insecticides, vaccines, and protein engineering scaffolds.
Structure
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.
Function
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.