Tityustoxin peptide 2
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] |
Sources
[edit]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]
Chemistry
[edit]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]
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Target
[edit]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]
Toxicity
[edit]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.
References
[edit]- ^ a b c d e f g Pimenta, Adriano M.C.; Legros, Christian; Almeida, Flavia de Marco; Mansuelle, Pascal; Bougis, Pierre E.; Martin-Eauclaire, Marie F. (2003). "Novel structural class of four disulfide-bridged peptides from Tityus serrulatus venom". Biochemical and Biophysical Research Communications. 301 (4): 1086–1092. doi:10.1016/S0006-291X(03)00082-2. PMID 12589824.
- ^ "SCOPe 2.05: Domain d2li7a_: 2li7 A". scop.berkeley.edu. Retrieved 2016-02-10.
- ^ "Superfamily - Tityustoxin peptide 2". supfam.cs.bris.ac.uk. Retrieved 2016-02-09.
- ^ a b c "Tityustoxin peptide 2 - Tityus serrulatus (Brazilian yellow scorpion)". uniprot.org. Retrieved 2016-09-25.
- ^ Structure function relationship of K+ion channel toxins:from cloning to functional characterization. Leuve, Belgium: Isabelle Huys. 2004. pp. 22–27. ISBN 9789058673534.
- ^ a b c "Family relationships - Tityustoxin peptide 2". ebi.ac.uk. Retrieved 2016-02-10.
- ^ Almeida, almeida.; Diego D., Scortecci; Katia C., Kobashi; Leonardo S., Agnes-Lima; Lucymara F, Fernandes Pedrosa. (2012). "Profiling the resting venom gland of the scorpion Tityus stigmurus through a transcriptomic survey". BMC Genomics. 13: 362. doi:10.1186/1471-2164-13-362. PMC 3444934. PMID 22853446.
- ^ a b Eauclaire, Martin; France, Marie; Pimenta, Adriano M. C.; Bougis, Pierre E; de Lima, Maria-Elenal (2016). "Potassium channel blockers from the venom of the Brazilian scorpion Tityus serrulatus". Toxicon. 119: 253–265. doi:10.1016/j.toxicon.2016.06.016. PMID 27349167.