1g92 | pdb_00001g92
SOLUTION STRUCTURE OF PONERATOXIN
Structural highlights
FunctionTX1A_PARCV Blocks nicotinic synaptic transmission in insect CNS and affects voltage-gated sodium channels (Nav). It is a strong, but very slowly acting agonist for smooth muscles and its blocks synaptic transmission in the insect CNS in a concentration-dependent manner and depolarizes giant interneurons. Also affects neuromuscular transmission in rat tissue.[1] Publication Abstract from PubMedPoneratoxin 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. Poneratoxin, a neurotoxin from ant venom. Structure and expression in insect cells and construction of a bio-insecticide.,Szolajska E, Poznanski J, Ferber ML, Michalik J, Gout E, Fender P, Bailly I, Dublet B, Chroboczek J Eur J Biochem. 2004 Jun;271(11):2127-36. PMID:15153103[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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