 |
|
 |
| |
| Toxin Name |
μ-cyrtautoxin-As1a |
| Source Species |
Apomastus schlingeri (Trap-door spider) |
| Toxin Group |
Cyrtautoxin |
| Description |
Insecticidal toxin that is lethal to larva of the tobacco hornworm Manduca sexta within 24 hours of injection but is much less potent against the beet armyworm Spodoptera exigua. μ-CUTX-As1a blocks insect voltage-gated sodium channels. Channel block is voltage-independent insofar as it occurs without significant alteration in the voltage-dependence of channel activation or steady-state inactivation. Thus, μ-CUTX-As1a appears to be a pore blocker that plugs the outer vestibule of insect voltage-gated sodium channels. μ-CUTX-As1a is also a weak blocker of insect voltage-gated calcium channels.
Structurally, μ-CUTX-As1a is an atypical knottin peptide; three of the disulfide bridges form a classical inhibitor cystine knot motif while the fourth disulfide (Cys26-Cys31) acts as a molecular staple that restricts the flexibility of an unusually large β hairpin loop. |
| Discovered |
1992 |
|
|
| This toxin last updated on May 01, 2015 |
|
| Current Taxonomy |
Historic Taxonomy |
| Kingdom |
Animalia |
| Phylum |
Arthropoda |
| Class |
Arachnida |
| Order |
Araneae |
| Infra-order |
Mygalomorphae |
| Family |
Cyrtaucheniidae |
| Genus |
Apomastus |
| Species |
schlingeri |
|
|
|
| Molecular Target |
ED50 |
IC50 |
Kd |
Pharmacophore |
Comment |
| Sodium channel, voltage-gated (para-type) (invertebrate) |
|
540.0
nM
|
|
|
IC50 is for block of Nav currents in cockroach dorsal unpaired median (DUM) neurons. Also blocks cloned Blatella germanica Nav channel expressed in Xenopus oocytes. |
| Taxon |
ED50 |
LD50 |
PD50 |
Qualitative Information |
| Spodoptera exigua |
|
|
|
LD50 is more than 2,660 pmol/g
|
| Lucilia cuprina |
|
|
700.0
pmol/g
|
Recombinant toxin, measured 24 hours after intra-thoracical injection
|
| Manduca sexta |
|
133.0
pmol/g
|
|
Native toxin, by injection. Calculated from literature LD50 value of 0.5 μg/g based on MW of 3761 Da for oxidized toxin.
|
|
| Original Deposition References |
Skinner W.S., Dennis P.A., Li J.P., Quistad G.B.
Toxicon 30:1043-1050 (1992)
Identification of insecticidal peptides from venom of the trap-door spider, Aptostichus schlingeri (Ctenizidae).
|
| Other References |
Bende N.S., Kang E., Herzig V., Bosmans F., Nicholson G.M., Mobli M., King G.F.
Biochemical Pharmacology 85:1542-1554 (2013)
The insecticidal neurotoxin Aps III is an atypical knottin peptide that potently blocks insect voltage-gated sodium channels
|
|
| Disulfide Bonds |
| Left Residue |
Right Residue |
Evidence |
| 1 |
15 |
Experimentally determined |
| 8 |
19 |
Experimentally determined |
| 14 |
35 |
Experimentally determined |
| 26 |
31 |
Experimentally determined |
|
|
| Peptide Sequences |
>as:mu-cyrtautoxin-As1a|sp:P49268 Insecticidal toxin mu-cyrtautoxin-As1a from the spider Apomastus schlingeri.
CNSKGTPCTNADECCGGKCAYNVWNCIGGGCSKTCGY |
Full BLAST |
BLAST mature toxin only
|
|
| Synonym |
Type |
| μ-cyrtautoxin-As1a |
Recommended full name |
| μ-CUTX-As1a |
Recommended abbreviation |
| Aptotoxin-3 |
Synonym |
| Aptotoxin III |
Synonym |
| Paralytic peptide III |
Synonym |
| PP III |
Synonym (abbreviation) |
| Aps III |
Synonym (abbreviation) |
|
|
|
|
|
 |
|
 |
|
|
