Chemistry: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
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
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
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
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
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 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. http://scop.berkeley.edu/sunid=242892. Retrieved 2016-02-10.
- ↑ "Superfamily - Tityustoxin peptide 2". supfam.cs.bris.ac.uk. http://supfam.cs.bris.ac.uk/SUPERFAMILY/cgi-bin/scop.cgi?sunid=57116. Retrieved 2016-02-09.
- ↑ 4.0 4.1 4.2 "Tityustoxin peptide 2 - Tityus serrulatus (Brazilian yellow scorpion)". uniprot.org. https://www.uniprot.org/uniprot/P0C175. 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. https://books.google.com/books?id=_ZizxAyUMIcC&q=Structure-function+relationship+of+K%2Bion+channel+toxins%3A+from+cloning+to+functional+characterization.&pg=PP12.
- ↑ 6.0 6.1 6.2 "Family relationships - Tityustoxin peptide 2". ebi.ac.uk. https://www.ebi.ac.uk/interpro/entry/IPR008911. 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. PMID 22853446.
- ↑ 8.0 8.1 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.
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