A new type of scorpion Na+-channel-toxin-like polypeptide active on K+ channels.

ABSTRACT: We have purified and characterized two peptides, named KAaH1 and KAaH2 (AaH polypeptides 1 and 2 active on K+ channels, where AaH stands for Androctonus australis Hector), from the venom of A. australis Hector scorpions. Their sequences contain 58 amino acids including six half-cysteines and differ only at positions 26 (Phe/Ser) and 29 (Lys/Gln). Although KAaH1 and KAaH2 show important sequence similarity with anti-mammal beta toxins specific for voltage-gated Na+ channels, only weak beta-like effects were observed when KAaH1 or KAaH2 (1 microM) were tested on brain Nav1.2 channels. In contrast, KAaH1 blocks Kv1.1 and Kv1.3 channels expressed in Xenopus oocytes with IC50 values of 5 and 50 nM respectively, whereas KAaH2 blocks only 20% of the current on Kv1.1 and is not active on Kv1.3 cha

SUBMITTER: Srairi-Abid N 

PROVIDER: S-EPMC1138952 | biostudies-literature | 2005 Jun

REPOSITORIES: biostudies-literature