title: Biochemical and biophysical combined study of bicarinalin, an ant venom antimicrobial peptide.
abstract: We have recently characterized bicarinalin as the most abundant peptide from the venom of the ant Tetramorium bicarinatum. This antimicrobial peptide is active against Staphylococcus and Enterobacteriaceae. To further investigate the antimicrobial properties of this cationic and cysteine-free peptide, we have studied its antibacterial, antifungal and antiparasitic activities on a large array of microorganisms. Bicarinalin was active against fifteen microorganisms with minimal inhibitory concentrations ranging from 2 and 25μmolL(-1). Cronobacter sakazakii, Salmonella enterica, Candida albicans, Aspergilus niger and Saccharomyces cerevisiae were particularly susceptible to this novel antimicrobial peptide. Resistant strains of Staphylococcus aureus, Pseudomonas aeruginosa and C. albicans were as susceptible as the canonical strains. Interestingly, bicarinalin was also active against the parasite Leishmania infantum with a minimal inhibitory concentrations of 2μmolL(-1). The bicarinalin pre-propeptide cDNA sequence has been determined using a combination of degenerated primers with RACE PCR strategy. Interestingly, the N-terminal domain of bicarinalin pre-propeptide exhibited sequence similarity with the pilosulin antimicrobial peptide family previously described in the Myrmecia venoms. Moreover, using SYTOX green uptake assay, we showed that, for all the tested microorganisms, bicarinalin acted through a membrane permeabilization mechanism. Two dimensional-NMR experiments showed that bicarinalin displayed a 10 residue-long α-helical structure flanked by two N- and C-terminal disordered regions. This partially amphipathic helix may explain the membrane permeabilization mechanism of bicarinalin observed in this study. Finally, therapeutic value of bicarinalin was highlighted by its low cytotoxicity against human lymphocytes at bactericidal concentrations and its long half-life in human serum which was around 15h.
authors.affiliation: Equipe EA 4357, VAcBio, Université de Toulouse, CUFR Champollion, Place de Verdun, 81012 Albi, France.
authors.forename: Nathan
authors.initials: N
authors.lastname: Téné
authors.affiliation: Equipe EA 4357, VAcBio, Université de Toulouse, CUFR Champollion, Place de Verdun, 81012 Albi, France.
authors.forename: Elsa
authors.initials: E
authors.lastname: Bonnafé
authors.affiliation: Equipe EA 4357, VAcBio, Université de Toulouse, CUFR Champollion, Place de Verdun, 81012 Albi, France.
authors.forename: Fanny
authors.initials: F
authors.lastname: Berger
authors.affiliation: Equipe EA 4357, VAcBio, Université de Toulouse, CUFR Champollion, Place de Verdun, 81012 Albi, France.
authors.forename: Aline
authors.initials: A
authors.lastname: Rifflet
authors.affiliation: Normandie Univ, COBRA, UMR 6014, IRIB, Université de Rouen, INSA de Rouen, CNRS, IRCOF, 1 rue Tesnière, 76821 Mont-Saint-Aignan, France.
authors.forename: Laure
authors.initials: L
authors.lastname: Guilhaudis
authors.affiliation: Normandie Univ, COBRA, UMR 6014, IRIB, Université de Rouen, INSA de Rouen, CNRS, IRCOF, 1 rue Tesnière, 76821 Mont-Saint-Aignan, France.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Ségalas-Milazzo
authors.affiliation: UMR 152-Pharma-Dev, Université de Toulouse, 31432 Toulouse, France.
authors.forename: Bernard
authors.initials: B
authors.lastname: Pipy
authors.affiliation: UMR 152-Pharma-Dev, Université de Toulouse, 31432 Toulouse, France.
authors.forename: Agnès
authors.initials: A
authors.lastname: Coste
authors.affiliation: Inserm U982, Laboratoire de Différenciation et Communication Neuronale et Neuroendocrine, Equipe Facteurs Neurotrophiques et Différenciation Neuronale, Plate-forme de Recherche en Imagerie Cellulaire de Haute-Normandie [PRIMACEN], IRIB, Université de Rouen, 76821 Mont-Saint-Aignan, France.
authors.forename: Jérôme
authors.initials: J
authors.lastname: Leprince
authors.affiliation: Equipe EA 4357, VAcBio, Université de Toulouse, CUFR Champollion, Place de Verdun, 81012 Albi, France. Electronic address: michel.treilhou@univ-jfc.fr.
authors.forename: Michel
authors.initials: M
authors.lastname: Treilhou
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000862:Ant Venoms / Q000737:chemistry / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology*; D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D000935:Antifungal Agents / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D023181:Antimicrobial Cationic Peptides / Q000737:chemistry / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology*; D000981:Antiprotozoal Agents / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D001000:Ants; D001483:Base Sequence; D002463:Cell Membrane Permeability; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D017124:Conserved Sequence; D006207:Half-Life; D006801:Humans; D019476:Insect Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology; D007928:Lethal Dose 50; D008214:Lymphocytes / Q000187:drug effects / Q000502:physiology; D008826:Microbial Sensitivity Tests; D008958:Models, Molecular; D010802:Phylogeny; D017433:Protein Structure, Secondary; D059748:Proteolysis
chemical_list: D000862:Ant Venoms; D000900:Anti-Bacterial Agents; D000935:Antifungal Agents; D023181:Antimicrobial Cationic Peptides; D000981:Antiprotozoal Agents; D019476:Insect Proteins; C581022:bicarinalin, Tetramorium bicarinatum
keywords: Ant venom; Antimicrobial peptide; Candida; Leishmania; Prepropeptide; Salmonella; Therapeutic index [TI]