Excitatory anti-insect selective scorpion β-toxin.

Polypeptide‚ of 77 amino acids cross-linked by 4 disulfide bridges. Recombinant toxin produced in Eschirichia coli initialy from Buthotus judaicus scorpion venom.

Toxic exclusively to insects. Effective dose 50% in blowfly larvae (ED50) = 14 ng/100 mg body weight. Equilibrium dissociation constant‚ Kd‚ determined in binding assays to cockroach neuronal membranes = 0.15 nM (ref. 3).

1. Froy, O., Zilberberg, N., Gordon, D., Turkov, M., Gilles, N., Stankiewicz, M., Pelhate, M., Loret, E., Oren, D., Shaanan, B. and Gurevitz, M. (1999) The putative bioactive surface of insect-selective scorpion excitatory neurotoxins. J.Biol.Chem. 274, 5769
2. Oren, D. A., Froy, O., Amit, E., Kleinberger-Doron, N., Gurevitz, M. and Shaanan, B. (1998) An excitatory scorpion toxin with a distinctive feature: an additional a-helix at the C-terminus and its implications for interaction with insect sodium channels.
3. Cohen, L., Karbat, I., Gilles, N., Froy, O., Angelovici, R., Gordon, D., Gurevitz, M.(2004) Dissect. of the functional surface of an anti-insect excit. toxin illuminates a putative 'hot spot' common to all scorpion beta-toxins affecting Na channels, J.Bi