Omega-atracotoxins (ACTX) form a family of neurotoxins that block insect but
not vertebrate voltage-gated calcium channels. Omega-ACTXs are environmentally
benign, insect-specific toxins that represent excellent leads for the
development of new pesticides. Omega-ACTXs comprise a disulfide-rich region
that has a [C-C-CC-C-C] arrangement and possess a Knottin scaffold (see
The omega-ACTX type 1 family contains 36 to 37-residue toxins with three
highly conserved but structurally disordered N-terminal residues, which
precede the first cysteine residue (see <PDB:1AXH>) [1,2,3,5]. This family
- Omega-ACTX Hv1a, Hv1b, Hv1c, Hv1d, Hv1e, Hv1f from Hadronyche versuta (Blue
mountains funnel-web spider) (Atrax versutus),
- Omega-ACTX Ar1a from Atrax robustus (Funnel-web spider),
- Omega-missulenatoxin-Mb1a from Missulena bradleyi (Eastern mouse spider).
The omega-ACTX type 2 family contains 43 to 45-residue toxins with a
disordered C-terminal lipophilic extension (see <PDB:1G9P>) [4,5]. This family
- Omega-ACTX Hv2a from Hadronyche versuta (Blue mountains funnel-web spider)
- Omega ACTX As2a, As2b from Atrax sp. Illawarra (Funnel-web spider),
- Omega ACTX Hi2a, Hi2b from Hadronyche infensa (Fraser island funnel-web
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'C': conserved cysteine involved in a disulfide bond.
'*': position of the pattern for type 1.
'#': position of the pattern for type 2.
We developed two signature patterns for omega-ACTXs, one for the type 1 family
and one for the type 2 family.
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