tailieunhanh - Báo cáo khoa học: 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 antParaponera clavata. It is stored in the venom reservoir as an inactive 25-residue peptide. Here we des-cribe both chemically synthesized poneratoxin and pon-eratoxin obtained by expression in insect cells. When expressed in insect cells, poneratoxin was observed attached to cell membranes. Both synthetic and recom-binant ponerotoxins were soluble below pH . The structure of synthetic poneratoxin was characterized by circular dichroism and solved by nuclear magnetic reso-nance. . | Eur. J. Biochem. 271 2127-2136 2004 FEBS 2004 doi Poneratoxin a neurotoxin from ant venom Structure and expression in insect cells and construction of a bio-insecticide Ewa Szolajska1. Jaroslaw Poznanski1. Miauel Lopez Ferber2 Joanna Michalik1 Evelvne Gout3 Pascal Fender3 Isabelle Bailly3 Bernard Dublet3 and Jadwiga Chroboczek3 1 Institute of Biochemistry and Biophysics IBB Polish Academy of Sciences Warsaw Poland 2Laboratoire de Pathologie Comparée UMR 5087 INRA-CNRS-Universite de Montpellier II St. Christol les Ales 3Institute of Structural Biology IBS Grenoble France 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 pon-eratoxin 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 . 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 ponera-toxin has a V shape with two a-helices connected by a b-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. Keywords synthetic poneratoxin recombinant poneratoxin baculovirus insecticide peptide atomic structure. Living organisms have developed natural toxins