Referenced in: none

Automatically associated channels: Kv1.2 , Kv1.3 , Slo1

Title: A selective blocker of Kv1.2 and Kv1.3 potassium channels from the venom of the scorpion Centruroides suffusus suffusus.

Authors: Gerardo Corzo, Ferenc Papp, Zoltan Varga, Omar Barraza, Pavel G Espino-Solis, Ricardo C Rodríguez de la Vega, Rezso Gaspar, Gyorgy Panyi, Lourival D Possani

Journal, date & volume: Biochem. Pharmacol., 2008 Oct 30 , 76, 1142-54

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/18786511

Abstract
A novel potassium channel blocker peptide was purified from the venom of the scorpion Centruroides suffusus suffusus by high-performance liquid chromatography and its amino acid sequence was completed by Edman degradation and mass spectrometry analysis. It contains 38 amino acid residues with a molecular weight of 4000.3Da, tightly folded by three disulfide bridges. This peptide, named Css20, was shown to block preferentially the currents of the voltage-dependent K+-channels Kv1.2 and Kv1.3. It did not affect several other ion channels tested at 10 nM concentration. Concentration-response curves of Css20 yielded an IC50 of 1.3 and 7.2 nM for Kv1.2- and Kv1.3-channels, respectively. Interestingly, despite the similar affinities for the two channels the association and dissociation rates of the toxin were much slower for Kv1.2, implying that different interactions may be involved in binding to the two channel types; an implication further supported by in silico docking analyses. Based on the primary structure of Css20, the systematic nomenclature proposed for this toxin is alpha-KTx 2.13.