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| Toxin Name |
κ-theraphotoxin-Ps1a |
| Source Species |
Paraphysa scrofa (Chilean copper tarantula) |
| Toxin Group |
Theraphotoxin |
| Description |
κ-TRTX-Ps1a, a short-loop ICK 'tarantula' toxin, blocks voltage-gated potassium (Kv) channels Kv4.2 and Kv4.3 by shifting channel activation to more depolarized potentials. Toxins with very similar primary structure have been reported from two different theraphosid spiders, Grammostola rosea (κ-TRTX-Gr1a, a weak blocker of mechanosensitive channels in rat astrocytes (Kd ~ 6 μM)) and Thrixopelma pruriens (β/ω-TRTX-Tp2a, a blocker of vertebrate voltage-gated sodium and calcium channels) |
| Discovered |
1999 |
|
Sex: Female, Prosoma length: 14mm
Photo courtesy of Martin Huesser
Use of photo governed by creative
commons noncommercial license
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| This toxin last updated on Sep 07, 2010 |
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| Current Taxonomy |
Historic Taxonomy |
| Kingdom |
Animalia |
| Phylum |
Arthropoda |
| Class |
Arachnida |
| Order |
Araneae |
| Infra-order |
Mygalomorphae |
| Family |
Theraphosidae |
| Genus |
Paraphysa |
| Species |
scrofa |
|
| Phrixotrichus chilensis |
| Phrixotrichus roseus |
| Phrixotrichus scrofa |
| Aranea scrofa |
| Mygale chilensis |
| Mygale rosea |
| Paraphysa manicata |
| Paraphysa scrofa |
| Phrixotrichus auratus |
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| Molecular Target |
ED50 |
IC50 |
Kd |
Pharmacophore |
Comment |
| Potassium channel, voltage-gated (vertebrate): KV4.3 |
|
28.0
nM
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Inhibition of Kv4.3 channels expressed in oocytes by native toxin |
| Potassium channel, voltage-gated (vertebrate): KV4.2 |
|
5.0
nM
|
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Inhibition of Kv4.2 channels expressed in oocytes by native toxin |
| Taxon |
ED50 |
LD50 |
PD50 |
Qualitative Information |
| Mus musculus |
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Up to 40 nM of the toxin i.v. cause generalized vasoconstriction, numerous transient cardiac adverse effects including premature ventricular beats, ventricular tachycardia, different degrees of atrio-ventricular block and it also prolongs the QT interval
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| Source |
Accession |
| ArachnoServer
|
AS000399 |
| NCBI_Taxon
|
269635
|
| PDB
|
1V7F
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| UniProt
|
P61230
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| Original Deposition References |
Diochot S., Drici M.-D., Moinier D., Fink M., Lazdunski M.
Br. J. Pharmacol. 126:251-263(1999).
Effects of phrixotoxins on the Kv4 family of potassium channels and implications for the role of Ito1 in cardiac electrogenesis.
|
Chagot B., Escoubas P., Villegas E., Bernard C., Ferrat G., Corzo G., Lazdunski M., Darbon H.
Protein Sci. 13:1197-1208(2004).
Solution structure of Phrixotoxin 1, a specific peptide inhibitor of Kv4 potassium channels from the venom of the theraphosid spider Phrixotrichus auratus.
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| Disulfide Bonds |
Posttranslational modifications |
| Left Residue |
Right Residue |
Evidence |
| 2 |
16 |
Experimentally determined |
| 9 |
21 |
Experimentally determined |
| 15 |
25 |
Experimentally determined |
|
| Residue Number |
Type |
Symbol |
| 29 |
C-terminal amidation (Probable) |
NH₂ |
|
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| Peptide Sequences |
>as:κ-theraphotoxin-Ps1a|sp:P61230 Toxin from venom of the spider Paraphysa scrofa that inhibits Kv4.2 and Kv4.3 channels
YCQKWMWTCDSARKCCEGLVCRLWCKKII |
Full BLAST |
BLAST mature toxin only
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| Synonym |
Type |
| κ-theraphotoxin-Ps1a |
Recommended full name |
| κ-TRTX-Ps1a |
Recommended abbreviation |
| Phrixotoxin-1 |
Synonym |
| PaTX1 |
Synonym (abbreviation) |
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