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| Toxin Name |
κ-theraphotoxin-Ps1b |
| Source Species |
Paraphysa scrofa (Chilean copper tarantula) |
| Toxin Group |
Theraphotoxin |
| Description |
κ-TRTX-Ps1b is a 'short-loop' ICK toxin that blocks voltage-gated potassium (Kv) channels Kv4.2 and Kv4.3 by shifting channel activation to more depolarized potentials. A toxin with identical primary structure (κ-TRTX-Gr2a) was reported in 2002 from a different theraphosid spider Grammostola rosea, and it was demonstrated to be a weak blocker of mechanosensitive channels in rat astrocytes (Kd ~ 6 μM). |
| 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 28, 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): KV4.2 |
|
34.0
nM
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Inhibition of Kv4.2 channels expressed in oocytes by native toxin |
| Potassium channel, voltage-gated (vertebrate): KV4.3 |
|
71.0
nM
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Inhibition of Kv4.3 channels expressed in oocytes by native toxin |
| Mechanosensitive ion channel |
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Inhibition of mechanosensitive channels in rat astrocytes by native toxin |
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| Source |
Accession |
| ArachnoServer
|
AS000402 |
| NCBI_Taxon
|
269635
|
| PDB
|
1LUP
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| UniProt
|
P61231
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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.
|
| Other References |
Oswald R.E., Suchyna T.M., McFeeters R., Gottlieb P.A., Sachs F.
J. Biol. Chem. 277:34443-34450 (2002)
Solution structure of peptide toxins that block mechanosensitive ion channels
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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 |
| 31 |
C-terminal amidation (Probable) |
NH₂ |
|
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| Peptide Sequences |
>as:κ-theraphotoxin-Ps1b|sp:P61231 Toxin from the spider Paraphysa scrofa that inhibits Kv4.2 and Kv4.3 channels
YCQKWMWTCDEERKCCEGLVCRLWCKRIINM |
Full BLAST |
BLAST mature toxin only
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| Synonym |
Type |
| κ-theraphotoxin-Ps1b |
Recommended full name |
| κ-TRTX-Ps1b |
Recommended abbreviation |
| Phrixotoxin-2 |
Synonym |
| PaTX2 |
Synonym (abbreviation) |
| GsMTx-2 |
Synonym (abbreviation) |
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