Poneratoxin, a neurotoxin from ant venom. Structure and expression in insect cells and construction of a bio-insecticide.
Poneratoxin is a small neuropeptide found in the venom of the ant Paraponera clavata. It is stored in the venom reservoir as an inactive 25-residue peptide. Here we describe both chemically synthesized poneratoxin and poneratoxin obtained by expression in insect cells. When expressed in insect cells, poneratoxin was observed attached to cell membranes. Both synthetic and recombinant ponerotoxins were soluble below pH 4.5. The structure of synthetic poneratoxin was characterized by circular dichroism and solved by nuclear magnetic resonance. In an environment imitating a lipid bilayer, at pH within the range of insect hemolymph, synthetic poneratoxin has a V shape, with two alpha-helices connected by a beta-turn. Insect larvae were paralyzed by injection of either of the purified toxins, with the recombinant one acting faster. The recombinant toxin-producing baculovirus reduced the average survival time of the insect host by 25 h compared with unmodified virus. Mass spectrometry analysis showed that the recombinant toxin has an N-terminal 21-residue extension, possibly improving its stability and/or stabilizing the membrane-bound state. The potential use of poneratoxin for the construction of biological insecticide is discussed.
Szolajska
Ewa
E
Institute of Biochemistry and Biophysics (IBB), Polish Academy of Sciences, Warsaw, Poland.
Poznanski
Jaroslaw
J
Ferber
Miguel López
ML
Michalik
Joanna
J
Gout
Evelyne
E
Fender
Pascal
P
Bailly
Isabelle
I
Dublet
Bernard
B
Chroboczek
Jadwiga
J
D000818:Animals; D000862:Ant Venoms / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism* / Q000633:toxicity; D016367:Baculoviridae / Q000235:genetics; D002460:Cell Line; D002942:Circular Dichroism; D019476:Insect Proteins; D007306:Insecticides / Q000737:chemistry / Q000378:metabolism; D008958:Models, Molecular; D009479:Neuropeptides / Q000138:chemical synthesis / Q000737:chemistry / Q000633:toxicity; D009498:Neurotoxins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism* / Q000633:toxicity; D019906:Nuclear Magnetic Resonance, Biomolecular; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism / Q000633:toxicity; D018411:Spodoptera / Q000166:cytology / Q000378:metabolism
D000862:Ant Venoms; D019476:Insect Proteins; D007306:Insecticides; D009479:Neuropeptides; D009498:Neurotoxins; D011994:Recombinant Proteins; C072588:poneratoxin