Purification and cDNA cloning of a novel neurotoxic peptide (Acra3) from the scorpion Androctonus crassicauda

Peptides. 2012 Sep;37(1):106-12. doi: 10.1016/j.peptides.2012.07.009. Epub 2012 Jul 20.

Abstract

Androctonus crassicauda is one of the Southeastern Anatolian scorpions of Turkey with ethno-medical and toxicological importance. Two toxic peptides (Acra1 and Acra2) were isolated and characterized from the venom of this scorpion. In this communication, the isolation of an additional toxin (Acra3) by chromatographic separations (HPLC and TSK-gel sulfopropyl) and its chemical and functional characterization is reported. Acra3 is a 7620Da molecular weight peptide, with 66 amino acid residues crosslinked by four disulfide bridges. The gene coding for this peptide was cloned and sequenced. Acra3 is anticipated to undergo post-translational modifications at the C-terminal region, having an amidated serine as last residue. Injection of Acra3 induces severe neurotoxic events in mice, such as: excitability and convulsions, leading to the death of the animals within a few minutes after injection. Electrophysiological assays conducted with pure Acra3, using cells that specifically expressed sodium channels (Nav1.1-Nav1.6) showed no clear effect. The exact molecular target of Acra3 remained undiscovered, similar to three other scorpion peptides that clustered very closely in the phylogenetic tree included here. The exact target of these four peptides is not very clear.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Cell Line
  • Chromatography, Reverse-Phase
  • Cloning, Molecular
  • Conserved Sequence
  • Crustacea
  • DNA, Complementary / genetics
  • DNA, Complementary / isolation & purification
  • Gryllidae
  • Humans
  • Lethal Dose 50
  • Membrane Potentials / drug effects
  • Mice
  • Molecular Sequence Data
  • Peptides / genetics*
  • Peptides / isolation & purification
  • Peptides / pharmacology
  • Peptides / toxicity
  • Phylogeny
  • Scorpion Venoms / genetics*
  • Scorpion Venoms / isolation & purification
  • Scorpion Venoms / pharmacology
  • Scorpion Venoms / toxicity
  • Scorpions / genetics*
  • Sequence Analysis, DNA
  • Sequence Homology, Amino Acid

Substances

  • DNA, Complementary
  • Peptides
  • Scorpion Venoms

Associated data

  • GENBANK/GQ454796