The first potassium channel toxin from the venom of the Iranian scorpion Odonthobuthus doriae

The very first member of K+ channels toxins from the venom of the Iranian scorpion Odonthobuthus doriae (OdK1) was purified, sequenced and characterized physiologically. OdK1 has 29 amino acids, six conserved cysteines and a pI value of 4.95. Based on multiple sequence alignments, OdK1 was classified as alpha-KTx 8.5. The pharmacological effects of OdK1 were studied on six different cloned K+ channels (vertebrate Kv1.1-Kv1.5 and Shaker IR) expressed in Xenopus laevis oocytes. Interestingly, OdK1 selectively inhibited the currents through Kv1.2 channels with an IC50 value of 183 +/- 3 nM but did not affect any of the other channels. (c) 2006 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.