Axel Touchard1, Andreas Brust2, Fernanda Caldas Cardoso2, Yanni K-Y Chin2, Volker Herzig2, Ai-Hua Jin2, Alain Dejean3, Paul F Alewood2, Glenn F King2, Jérôme Orivel4, Pierre Escoubas5. 1. 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. 2. Institute for Molecular Bioscience, The University of Queensland, St Lucia, Queensland 4072, Australia. 3. 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. 4. CNRS, UMR Ecologie des forêts de Guyane (AgroParisTech, CIRAD, CNRS, INRA, Université de Guyane, Université des Antilles), Campus Agronomique, BP 316, 97379 Kourou, France. 5. VenomeTech, 473 Route des Dolines, 06560 Valbonne, France.
Abstract
BACKGROUND: 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. METHODS: 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. RESULTS: 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). CONCLUSIONS: Poneritoxins from Anochetus emarginatus venom are a novel class of toxins that are structurally unique among animal venoms. GENERAL SIGNIFICANCE: 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. Crown
BACKGROUND: 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. METHODS: 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. RESULTS: 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). CONCLUSIONS: Poneritoxins from Anochetus emarginatus venom are a novel class of toxins that are structurally unique among animal venoms. GENERAL SIGNIFICANCE: 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. Crown
Authors: David A Eagles; Natalie J Saez; Bankala Krishnarjuna; Julia J Bradford; Yanni K-Y Chin; Hana Starobova; Alexander Mueller; Melissa E Reichelt; Eivind A B Undheim; Raymond S Norton; Walter G Thomas; Irina Vetter; Glenn F King; Samuel D Robinson Journal: Proc Natl Acad Sci U S A Date: 2022-02-15 Impact factor: 12.779