title: Isolation and characterization of a structurally unique β-hairpin venom peptide from the predatory ant Anochetus emarginatus.
abstract: Most ant venoms consist predominantly of small linear peptides, although some contain disulfide-linked peptides as minor components. However, in striking contrast to other ant species, some Anochetus venoms are composed primarily of disulfide-rich peptides. In this study, we investigated the venom of the ant Anochetus emarginatus with the aim of exploring these novel disulfide-rich peptides.
  
  
  
  The venom peptidome was initially investigated using a combination of reversed-phase HPLC and mass spectrometry, then the amino acid sequences of the major peptides were determined using a combination of Edman degradation and de novo MS/MS sequencing. We focused on one of these peptides, U1-PONTX-Ae1a (Ae1a), because of its novel sequence, which we predicted would form a novel 3D fold. Ae1a was chemically synthesized using Fmoc chemistry and its 3D structure was elucidated using NMR spectroscopy. The peptide was then tested for insecticidal activity and its effect on a range of human ion channels.
  
  
  
  Seven peptides named poneritoxins (PONTXs) were isolated and sequenced. The three-dimensional structure of synthetic Ae1a revealed a novel, compact scaffold in which a C-terminal β-hairpin is connected to the N-terminal region via two disulfide bonds. Synthetic Ae1a reversibly paralyzed blowflies and inhibited human L-type voltage-gated calcium channels (CaV1).
  
  
  
  Poneritoxins from Anochetus emarginatus venom are a novel class of toxins that are structurally unique among animal venoms.
  
  
  
  This study demonstrates that Anochetus ant venoms are a rich source of novel ion channel modulating peptides, some of which might be useful leads for the development of biopesticides.
authors.affiliation: CNRS, UMR Ecologie des forêts de Guyane (AgroParisTech, CIRAD, CNRS, INRA, Université de Guyane, Université des Antilles), Campus Agronomique, BP 316, 97379 Kourou, France. Electronic address: t.axel@hotmail.fr.
authors.forename: Axel
authors.initials: A
authors.lastname: Touchard
authors.affiliation: Institute for Molecular Bioscience, The University of Queensland, St Lucia, Queensland 4072, Australia.
authors.forename: Andreas
authors.initials: A
authors.lastname: Brust
authors.affiliation: Institute for Molecular Bioscience, The University of Queensland, St Lucia, Queensland 4072, Australia.
authors.forename: Fernanda Caldas
authors.initials: FC
authors.lastname: Cardoso
authors.affiliation: Institute for Molecular Bioscience, The University of Queensland, St Lucia, Queensland 4072, Australia.
authors.forename: Yanni K-Y
authors.initials: YK
authors.lastname: Chin
authors.affiliation: Institute for Molecular Bioscience, The University of Queensland, St Lucia, Queensland 4072, Australia.
authors.forename: Volker
authors.initials: V
authors.lastname: Herzig
authors.affiliation: Institute for Molecular Bioscience, The University of Queensland, St Lucia, Queensland 4072, Australia.
authors.forename: Ai-Hua
authors.initials: AH
authors.lastname: Jin
authors.affiliation: CNRS, UMR Ecologie des forêts de Guyane (AgroParisTech, CIRAD, CNRS, INRA, Université de Guyane, Université des Antilles), Campus Agronomique, BP 316, 97379 Kourou, France; CNRS, UMR 5245, Laboratoire Écologie Fonctionnelle et Environnement, 118 route de Narbonne, 31062 Toulouse, France; Université de Toulouse, UPS, INP, Ecolab, Toulouse, France.
authors.forename: Alain
authors.initials: A
authors.lastname: Dejean
authors.affiliation: Institute for Molecular Bioscience, The University of Queensland, St Lucia, Queensland 4072, Australia.
authors.forename: Paul F
authors.initials: PF
authors.lastname: Alewood
authors.affiliation: Institute for Molecular Bioscience, The University of Queensland, St Lucia, Queensland 4072, Australia.
authors.forename: Glenn F
authors.initials: GF
authors.lastname: King
authors.affiliation: CNRS, UMR Ecologie des forêts de Guyane (AgroParisTech, CIRAD, CNRS, INRA, Université de Guyane, Université des Antilles), Campus Agronomique, BP 316, 97379 Kourou, France.
authors.forename: Jérôme
authors.initials: J
authors.lastname: Orivel
authors.affiliation: VenomeTech, 473 Route des Dolines, 06560 Valbonne, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Escoubas
mesh_terms: D020816:Amino Acid Motifs; D000862:Ant Venoms / Q000737:chemistry*; D004220:Disulfides / Q000737:chemistry
chemical_list: D000862:Ant Venoms; D004220:Disulfides
keywords: Anochetus; Ant venom; Disulfide-rich peptides; L-type calcium channels; Neurotoxin; Poneritoxins; U(1)-PONTX-Ae1a