BOT IT2 - A NEW SCORPION TOXIN TO STUDY RECEPTOR-SITE ON INSECT SODIUM-CHANNELS

The insect-specific Bothus occitanus tunetanus IT2 toxin is distinguis hable from other scorpion toxins by its amino acid sequence and effect s on sodium conductance. The present study reveals that Bot IT2 posses ses in cockroach neuronal membranes a single class of high affinity (K -d = 0.3 +/- 0.1 nM) and low capacity (B-max = 2.4 +/- 0.5 pmol/mg) bi nding sites. Competitive binding experiments with several known sodium channel neurotoxins reveal that the Bot IT2 binding site is in close proximity to the other toxins. (C) 1997 Federation of European Biochem ical Societies.