Specific membrane binding of neurotoxin II can facilitate its delivery to acetylcholine receptor

Biophys J. 2009 Oct 7;97(7):2089-97. doi: 10.1016/j.bpj.2009.07.037.

Abstract

The action of three-finger snake alpha-neurotoxins at their targets, nicotinic acetylcholine receptors (nAChR), is widely studied because of its biological and pharmacological relevance. Most such studies deal only with ligands and receptor models; however, for many ligand/receptor systems the membrane environment may affect ligand binding. In this work we focused on binding of short-chain alpha-neurotoxin II (NTII) from Naja oxiana to the native-like lipid bilayer, and the possible role played by the membrane in delivering the toxin to nAChR. Experimental (NMR and mutagenesis) and molecular modeling (molecular-dynamics simulation) studies revealed a specific interaction of the toxin molecule with the phosphatidylserine headgroup of lipids, resulting in the proper topology of NTII on lipid bilayers favoring the attack of nAChR. Analysis of short-chain alpha-neurotoxins showed that most of them possess a high positive charge and sequence homology in the lipid-binding motif of NTII, implying that interaction with the membrane surrounding nAChR may be common for the toxin family.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Binding Sites
  • Biomimetics
  • Cell Membrane / chemistry
  • Cell Membrane / metabolism*
  • Elapidae
  • Lipid Bilayers / chemistry
  • Lipid Bilayers / metabolism
  • Liposomes / chemistry
  • Liposomes / metabolism
  • Magnetic Resonance Spectroscopy
  • Models, Molecular
  • Molecular Sequence Data
  • Mutagenesis
  • Mutation
  • Neurotoxins / chemistry
  • Neurotoxins / genetics
  • Neurotoxins / metabolism*
  • Protein Conformation
  • Receptors, Cholinergic / metabolism*
  • Substrate Specificity
  • Surface Properties
  • Torpedo

Substances

  • Lipid Bilayers
  • Liposomes
  • Neurotoxins
  • Receptors, Cholinergic