Tityustoxin peptide 2 (TsPep2) is a peptide isolated from the venom of the Tityus serrulatus (Brazilian yellow scorpion). It belongs to a class of short peptides, together with Tityustoxin peptide 1 and Tityustoxin peptide 3. [1]
| SCOP classification [2] | |
|---|---|
| Class | Small proteins |
| Superfamily | Scorpion toxin-like |
| Family | Short-chain scorpion toxin [3] |
| Species | Tityus serrulatus |
| UniProt | P0C175 [4] |
Tityus serrulatus, also known as the Brazilian yellow scorpion, is from the genus Tityus belonging to the family Buthidae .
TsPep2 is identified from the venom of Tityus serrulatus by using a cDNA primer sequence based on the C-terminal amino acid sequence of KTx2 from Androctonus australis . [1] [5]
The original encoded sequence of TsPep2 consists of 68 amino acids processed in a mature peptide of 29 amino acids with a final molecular weight of 2993.59 Da. [1] [6] TsPep2 differs in the mature sequence from TsPep3 only in one amino acid and TsPep1 shows 58,6% of sequence homology with Tspep2 and TsPep3. [1]
| 10 | 20 | 30 | 40 | 50 | 60 |
| MKFSCGFLLI | FLVLSAMIAT | FSEVEATVKC | GGCNRKCCAG | GCRSGKCING | KCQCYGRSDL NEEFENYQ |
Eight cysteines establish four disulfide bridges and a C-terminal tyrosine amide is present in the 55th position. Furthermore, TsPep2 sequence alignment shows that a part of the amino acid consensus sequence (CXXXKCCXC) involved in the pore blocking mechanism is present as in other known short scorpion toxins. [1] [6] [7]
It seems likely that TsPep2 has inhibitory actions on potassium channels, based on its sequence similarities in the C-terminal beta sheet with the potassium channel inhibitory alpha family (α-KTX) and on its similarities in the patterns of disulfide bridges with other short scorpion venom toxins. [1] [6] [8]
The biological function of TsPep2 is not clear yet, except from a small displacement on the 125I-KTX binding site on rat brain synaptosomes. [8] However, it has been shown that this peptide is not toxic to mice. [1] [4] The LD50 of TsPep2 is currently unknown.
Tityustoxin is a toxin found in the venom of scorpions from the subfamily Tityinae. By binding to voltage-dependent sodium ion channels and potassium channels, they cause sialorrhea, lacrimation and rhinorrhea.
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Butantoxin (BuTX) is a compound of the venom of three Brazilian and an Argentinean scorpion species of the genus Tityus. Butantoxin reversibly blocks the voltage-gated K+ channels Shaker B and Kv1.2, and the Ca2+-activated K+ channelsKCa 1.1 and KCa 3.1.
Pi3 toxin is a purified peptide derivative of the Pandinus imperator scorpion venom. It is a potent blocker of voltage-gated potassium channel, Kv1.3 and is closely related to another peptide found in the venom, Pi2.
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TsIV is a toxin from the venom of the Brazilian scorpion Tityus serrulatus which slows the inactivation of sodium channels.
AmmTX3, produced by Androctonus mauretanicus, is a scorpion toxin of the α-KTX15 subfamily. The toxin is known for its ability to act as a specific Kv4 channel blocker, and thereby reducing the A-type potassium current through this channel.
HsTx1 is a toxin from the venom of the scorpion Heterometrus spinifer. HsTx1 is a very potent inhibitor of the rat Kv1.3 voltage-gated potassium channel.
Spinoxin is a 34-residue peptide neurotoxin isolated from the venom of the Malaysian black scorpion Heterometrus spinifer. It is part of the α-KTx6 subfamily and exerts its effects by inhibiting voltage-gated potassium channels, specifically Kv1.2 and Kv1.3.
Ts15 is produced by the Brazilian yellow scorpion Tityus serrulatus. It targets voltage-gated potassium channels, primarily the subtypes Kv1.2 and Kv1.3.
HgeTx1 (systematic name: α-KTx 6.14) is a toxin produced by the Mexican scorpion Hoffmanihadrurus gertschi that is a reversible blocker of the Shaker B K+-channel, a type of voltage-gated potassium channels.
AaTX1 is a scorpion toxin of the α-KTx15 subfamily originally found in the venom of Androctonus australis. The toxin acts as a specific blocker on Kv4.3 voltage-gated potassium channel, thereby abolishing the A-type potassium currents.
ImKTx88 is a selective inhibitor of the Kv1 ion channel family that can be isolated from the venom of the Isometrus maculatus. This peptide belongs to the α-KTx subfamily and is classified as a pore-blocking toxin.
BmP02, also known as α-KTx 9.1 or Bmkk(6), is a toxin from the Buthus Martensi Karsch (BmK) scorpion. The toxin acts on potassium channels, blocking Kv1.3 and slowing the deactivation of Kv4.2. BmP02 is not toxic to humans or mice.
Pi5 toxin is a peptide found in the venom of the African emperor scorpion Pandinus imperator. Pi5 inhibits human Kv1.2 and Kv1.3 channels as well as Drosophila Shaker B potassium channels.
MeuKTX, which belongs to the α-KTx toxin subfamily, is a neurotoxin present in the venom of Mesobuthus eupeus. This short-chain peptide blocks potassium channels, such as Kv1.1, Kv1.2 and Kv1.3.
