The scorpion toxin Bot IX is a potent member of the α-like family and has a unique N-terminal sequence extension

FEBS Lett. 2016 Sep;590(18):3221-32. doi: 10.1002/1873-3468.12357. Epub 2016 Sep 1.

Abstract

We report the detailed chemical, immunological and pharmacological characterization of the α-toxin Bot IX from the Moroccan scorpion Buthus occitanus tunetanus venom. Bot IX, which consists of 70 amino acids, is a highly atypical toxin. It carries a unique N-terminal sequence extension and is highly lethal in mice. Voltage clamp recordings on oocytes expressing rat Nav1.2 or insect BgNav1 reveal that, similar to other α-like toxins, Bot IX inhibits fast inactivation of both variants. Moreover, Bot IX belongs to the same structural/immunological group as the α-like toxin Bot I. Remarkably, radioiodinated Bot IX competes efficiently with the classical α-toxin AaH II from Androctonus australis, and displays one of the highest affinities for Nav channels.

Keywords: Nav channel; scorpion toxin; α-like toxin.

Publication types

  • Letter

MeSH terms

  • Animals
  • Cell Line
  • Cockroaches
  • Male
  • Mice
  • Mice, Inbred C57BL
  • NAV1.2 Voltage-Gated Sodium Channel / metabolism
  • Protein Domains
  • Rats
  • Scorpion Venoms / chemistry
  • Scorpion Venoms / pharmacology
  • Scorpion Venoms / toxicity*
  • Sodium Channel Blockers / chemistry
  • Sodium Channel Blockers / pharmacology
  • Sodium Channel Blockers / toxicity*
  • Xenopus

Substances

  • NAV1.2 Voltage-Gated Sodium Channel
  • Scn2A protein, rat
  • Scorpion Venoms
  • Sodium Channel Blockers
  • alpha-toxin IX, Buthus occitanus tunetanus