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| Toxin Name |
μ-theraphotoxin-Phlo1b |
| Source Species |
Phlogius sp. |
| Toxin Group |
Theraphotoxin |
| Description |
Gating modifier toxin that inhibits the human voltage-gated sodium channel NaV1.7 (hNaV1.7) by shifting the threshold for channel activation to more positive potentials. Toxin shifts the V0.5 for hNaV1.7 activation by +4.6 mV at 300 nM and +10.2 mV at 1 μM. Furthermore, inhibition of hNaV1.7 is voltage-dependent, with lower inhibition at more positive test pulses. μ-TRTX-Phlo1b is a moderately potent inhibitor of hNaV1.7 (IC50 ~ 360 nm) with lower potency against hNaV1.2 (37% inhibition at 1 μM peptide) and hNaV1.5 (<20% inhibition at 1 μM peptide).
Sequence and cysteine spacing indicates that μ-TRTX-Phlo1b is an inhibitor cystine knot toxin that belongs to NaSpTx family 2. μ-TRTX-Phlo1b and μ-TRTX-Phlo1a are paralogs that only differ at their C-terminal residue. |
| Discovered |
2014 |
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Sex: female, Prosoma length: 30mm
Photo courtesy of Eivind Undheim
Use of photo governed by creative
commons noncommercial license
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| This toxin last updated on Jan 14, 2016 |
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| Current Taxonomy |
| Kingdom |
Animalia |
| Phylum |
Arthropoda |
| Class |
Arachnida |
| Order |
Araneae |
| Infra-order |
Mygalomorphae |
| Family |
Theraphosidae |
| Genus |
Phlogius |
| Species |
sp. |
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| Molecular Target |
ED50 |
IC50 |
Kd |
Pharmacophore |
Comment |
| Sodium channel, voltage-gated (vertebrate): NaV1.2 |
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1 μM toxin causes 37% inhibition of human Nav1.2 expressed in oocytes. |
| Sodium channel, voltage-gated (vertebrate): NaV1.5 |
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1 μM toxin causes less than 20% inhibition of human Nav1.5 expressed in oocytes. |
| Sodium channel, voltage-gated (vertebrate): NaV1.7 |
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360.0
nM
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Inhibition of human Nav1.7 expressed in oocytes by native toxin. |
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| Original Deposition References |
Chow, C.Y., Cristofori-Armstrong, B., Undheim, E.A.B., King, G.F., Rash, L.D.
Toxins 7: 2494-2513 (2015)
Three peptide modulators of the human voltage-gated sodium channel 1.7, an important analgesic target, from the venom of an Australian tarantula
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| Other References |
Klint J.K., Senff S., Rupasinghe D.B., Er S.Y., Herzig V., Nicholson G.M., King G.F.
Toxicon 60:478-91(2012).
Spider-venom peptides that target voltage-gated sodium channels: pharmacological tools and potential therapeutic leads.
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| Disulfide Bonds |
Posttranslational modifications |
| Left Residue |
Right Residue |
Evidence |
| 2 |
16 |
By homology |
| 9 |
21 |
By homology |
| 15 |
29 |
By homology |
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| Residue Number |
Type |
Symbol |
| 35 |
C-terminal amidation |
NH₂ |
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| Peptide Sequences |
>as:μ-theraphotoxin-Phlo1b Toxin from venom of the spider Phlogius sp. that inhibits the human voltage-gated sodium channel Nav1.7
MKVSVLITLAVLGVMFVWTSAAEQEDHGSDRRDSPALLKSLGRVFQSEERACRELLGGCS
KDSDCCAHLECRKKWPYHCVWDWTFGNEKS |
Full BLAST |
BLAST mature toxin only
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| mRNA Sequences |
>as:μ-theraphotoxin-Phlo1b cDNA sequence encoding the toxin μ-theraphotoxin-Phlo1b from the spider Phlogius sp.
ATGAAGGTTTCAGTACTAATAACTCTTGCTGTATTGGGGGTGATGTTTGTTTGGACTTCT
GCTGCTGAACAAGAAGATCATGGTTCGGATCGAAGGGACTCACCTGCATTGCTAAAATCT
CTGGGGAGAGTATTCCAGTCTGAGGAAAGAGCCTGCAGGGAACTGCTTGGAGGCTGTAGT
AAAGATTCCGATTGCTGTGCACACTTGGAATGCCGAAAAAAGTGGCCATATCATTGTGTG
TGGGATTGGACCTTCGGCAATGAGAAATCCTGA |
Full BLAST
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| Synonym |
Type |
| μ-theraphotoxin-Phlo1b |
Recommended full name |
| μ-TRTX-Phlo1b |
Recommended abbreviation |
| Phlo1b |
Synonym |
| Phlo1b |
Synonym (abbreviation) |
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