PROSITE documentation PDOC60016
Omega-atracotoxin (ACTX) families signatures


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 <PDOC60004>) [1,2,3,4,5].

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 includes:

  • 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 includes:

 - Omega-ACTX  Hv2a from Hadronyche versuta (Blue mountains funnel-web spider)
   (Atrax versutus),
 - Omega ACTX As2a, As2b from Atrax sp. Illawarra (Funnel-web spider),
 - Omega  ACTX  Hi2a,  Hi2b  from Hadronyche infensa (Fraser island funnel-web

                                   |                  |
                      ********     ######             |
                      |      |      |   |
                      +------|------+   |
'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.

Expert(s) to contact by email:

Ramakumar S.

Last update:

June 2005 / First entry.


Technical section

PROSITE methods (with tools and information) covered by this documentation:

OMEGA_ACTX_1, PS60016; Omega-atracotoxin (ACTX) type 1 family signature  (PATTERN)

OMEGA_ACTX_2, PS60017; Omega-atracotoxin (ACTX) type 2 family signature  (PATTERN)


1AuthorsFletcher J.I. Smith R. O'Donoghue S.I. Nilges M. Connor M. Howden M.E.H. Christie M.J. King G.F.
TitleThe structure of a novel insecticidal neurotoxin, omega-atracotoxin-HV1, from the venom of an Australian funnel web spider.
SourceNat. Struct. Biol. 4:559-566(1997).
PubMed ID9228949

2AuthorsWang X. Smith R. Fletcher J.I. Wilson H. Wood C.J. Howden M.E.H. King G.F.
TitleStructure-function studies of omega-atracotoxin, a potent antagonist of insect voltage-gated calcium channels.
SourceEur. J. Biochem. 264:488-494(1999).
PubMed ID10491095

3AuthorsTedford H.W. Gilles N. Menez A. Doering C.J. Zamponi G.W. King G.F.
TitleScanning mutagenesis of omega-atracotoxin-Hv1a reveals a spatially restricted epitope that confers selective activity against insect calcium channels.
SourceJ. Biol. Chem. 279:44133-44140(2004).
PubMed ID15308644

4AuthorsWang X. Connor M. Wilson D. Wilson H.I. Nicholson G.M. Smith R. Shaw D. Mackay J.P. Alewood P.F. Christie M.J. King G.F.
TitleDiscovery and structure of a potent and highly specific blocker of insect calcium channels.
SourceJ. Biol. Chem. 276:40306-40312(2001).
PubMed ID11522785

5AuthorsCorzo G. Escoubas P.
TitlePharmacologically active spider peptide toxins.
SourceCell. Mol. Life Sci. 60:2409-2426(2003).
PubMed ID14625686


PROSITE is copyrighted by the SIB Swiss Institute of Bioinformatics and distributed under the Creative Commons Attribution-NonCommercial-NoDerivatives (CC BY-NC-ND 4.0) License, see prosite_license.html.


View entry in original PROSITE document format
View entry in raw text format (no links)