2MI5 image
Entry Detail
PDB ID:
2MI5
Keywords:
Title:
Structure of insect-specific sodium channel toxin mu-Dc1a
Biological Source:
Source Organism:
Host Organism:
PDB Version:
Deposition Date:
2013-12-08
Release Date:
2014-07-23
Method Details:
Experimental Method:
Conformers Calculated:
200
Conformers Submitted:
20
Selection Criteria:
Best MolProbity score
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:Mu-diguetoxin-Dc1a
Chain IDs:A
Chain Length:57
Number of Molecules:1
Biological Source:Diguetia canities
Ligand Molecules
Primary Citation
A distinct sodium channel voltage-sensor locus determines insect selectivity of the spider toxin Dc1a.
Nat Commun 5 4350 4350 (2014)
PMID: 25014760 DOI: 10.1038/ncomms5350

Abstact

β-Diguetoxin-Dc1a (Dc1a) is a toxin from the desert bush spider Diguetia canities that incapacitates insects at concentrations that are non-toxic to mammals. Dc1a promotes opening of German cockroach voltage-gated sodium (Nav) channels (BgNav1), whereas human Nav channels are insensitive. Here, by transplanting commonly targeted S3b-S4 paddle motifs within BgNav1 voltage sensors into Kv2.1, we find that Dc1a interacts with the domain II voltage sensor. In contrast, Dc1a has little effect on sodium currents mediated by PaNav1 channels from the American cockroach even though their domain II paddle motifs are identical. When exploring regions responsible for PaNav1 resistance to Dc1a, we identified two residues within the BgNav1 domain II S1-S2 loop that when mutated to their PaNav1 counterparts drastically reduce toxin susceptibility. Overall, our results reveal a distinct region within insect Nav channels that helps determine Dc1a sensitivity, a concept that will be valuable for the design of insect-selective insecticides.

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Primary Citation of related structures