2M36

Solution structure of the insecticidal spider-venom peptide Aps III


Experimental Data Snapshot

  • Method: SOLUTION NMR
  • Conformers Calculated: 200 
  • Conformers Submitted: 20 
  • Selection Criteria: Best MolProbity scores 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

The insecticidal neurotoxin Aps III is an atypical knottin peptide that potently blocks insect voltage-gated sodium channels.

Bende, N.S.Kang, E.Herzig, V.Bosmans, F.Nicholson, G.M.Mobli, M.King, G.F.

(2013) Biochem Pharmacol 85: 1542-1554

  • DOI: 10.1016/j.bcp.2013.02.030

  • PubMed Abstract: 
  • One of the most potent insecticidal venom peptides described to date is Aps III from the venom of the trapdoor spider Apomastus schlingeri. Aps III is highly neurotoxic to lepidopteran crop pests, making it a promising candidate for bioinsecticide de ...

    One of the most potent insecticidal venom peptides described to date is Aps III from the venom of the trapdoor spider Apomastus schlingeri. Aps III is highly neurotoxic to lepidopteran crop pests, making it a promising candidate for bioinsecticide development. However, its disulfide-connectivity, three-dimensional structure, and mode of action have not been determined. Here we show that recombinant Aps III (rAps III) is an atypical knottin peptide; three of the disulfide bridges form a classical inhibitor cystine knot motif while the fourth disulfide acts as a molecular staple that restricts the flexibility of an unusually large β hairpin loop that often houses the pharmacophore in this class of toxins. We demonstrate that the irreversible paralysis induced in insects by rAps III results from a potent block of insect voltage-gated sodium channels. Channel block by rAps III is voltage-independent insofar as it occurs without significant alteration in the voltage-dependence of channel activation or steady-state inactivation. Thus, rAps III appears to be a pore blocker that plugs the outer vestibule of insect voltage-gated sodium channels. This mechanism of action contrasts strikingly with virtually all other sodium channel modulators isolated from spider venoms that act as gating modifiers by interacting with one or more of the four voltage-sensing domains of the channel.


    Related Citations: 
    • Identification of insecticidal peptides from venom of the trap-door spider, Aptostichus schlingeri (Ctenizidae).
      Skinner, W.S.,Dennis, P.A.,Li, J.P.,Quistad, G.B.
      (1992) Toxicon 30: 1043


    Organizational Affiliation

    Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD 4072, Australia.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
U2-cyrtautoxin-As1a
A
38Apomastus schlingeriN/A
Find proteins for P49268 (Apomastus schlingeri)
Go to UniProtKB:  P49268
Experimental Data & Validation

Experimental Data

  • Method: SOLUTION NMR
  • Conformers Calculated: 200 
  • Conformers Submitted: 20 
  • Selection Criteria: Best MolProbity scores 
  • Olderado: 2M36 Olderado

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2013-03-27
    Type: Initial release
  • Version 1.1: 2013-05-08
    Type: Database references