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| Toxin Name |
κ-theraphotoxin-Gr2a |
| Source Species |
Grammostola rosea (Chilean rose tarantula) |
| Toxin Group |
Theraphotoxin |
| Description |
κ-TRTX-Gr2a is a weak blocker of mechanosensitive channels in rat astrocytes (Kd ~ 6 μM). A toxin with identical primary structure (κ-TRTX-Ps1b) was reported in 1999 from a different theraphosid spider, Paraphysa scrofa, and it was demonstrated to block mammalian Kv4.2 and Kv4.3 with much higher potency than its inhibition of mechanosensitive channels. |
| Discovered |
1999 |
|
Sex: female, Prosoma length: 26mm
Photo courtesy of Bastian Rast
Use of photo governed by creative
commons noncommercial license
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| This toxin last updated on Dec 09, 2009 |
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| Current Taxonomy |
Historic Taxonomy |
| Kingdom |
Animalia |
| Phylum |
Arthropoda |
| Class |
Arachnida |
| Order |
Araneae |
| Infra-order |
Mygalomorphae |
| Family |
Theraphosidae |
| Genus |
Grammostola |
| Species |
rosea |
|
| Citharoscelus kochii |
| Citharoscelus spatulatus |
| Eurypelma rosea |
| Eurypelma spatulatum |
| Grammostola argentinense |
| Grammostola argentinensis |
| Grammostola cala |
| Grammostola rosea |
| Grammostola spathulata |
| Grammostola spatulata |
| Grammostola spatulatus |
| Lasiodora rosea |
| Mygale rosea |
| Mygale rubiginosa |
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| Molecular Target |
ED50 |
IC50 |
Kd |
Pharmacophore |
Comment |
| Mechanosensitive ion channel: Eukaryotic mechanosensitive channel |
|
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6000.0
nM
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Inhibition of mechanosensitive channels in rat astrocytes by native toxin |
| Potassium channel, voltage-gated (vertebrate): KV4.2 |
|
34.0
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Inhibition of rat 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 rat Kv4.3 channels expressed in oocytes by native toxin |
|
| Source |
Accession |
| ArachnoServer
|
AS000067 |
| NCBI_Taxon
|
432528
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| PDB
|
1LUP
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| UniProt
|
P60273
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| Original Deposition References |
Diochot S., Drici M.D., Moinier D., Fink M., Lazdunski M.
Br. J. Pharmacol. 126:251-63 (1999)
Effects of phrixotoxins on the Kv4 family of potassium channels and implicationsfor the role of Ito1 in cardiac electrogenesis.
|
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 |
| Left Residue |
Right Residue |
Evidence |
| 2 |
16 |
Experimentally determined |
| 9 |
21 |
Experimentally determined |
| 15 |
25 |
Experimentally determined |
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| Peptide Sequences |
>as:κ-theraphotoxin-Gr2a|sp:P60273 Toxin from the spider Grammostola rosea that inhibits Kv4.2 and Kv4.3 channels
YCQKWMWTCDEERKCCEGLVCRLWCKRIINM |
Full BLAST |
BLAST mature toxin only
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| Synonym |
Type |
| κ-theraphotoxin-Gr2a |
Recommended full name |
| κ-TRTX-Gr2a |
Recommended abbreviation |
| GsMTx-2 |
Synonym |
| Phrixotoxin-2 |
Synonym |
| MTx2 |
Synonym (abbreviation) |
| PaTX2 |
Synonym (abbreviation) |
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