Molecular cloning of a novel putative potassium channel-blocking neurotoxin from the venom of the North African scorpion, Androctonus amoreuxi

Scorpion venoms are a particularly rich source of neurotoxic proteins/peptides that interact in a highly specific fashion with discrete subtypes of ion channels in excitable and non-excitable cells. Here we have employed a recently developed technique to effect molecular cloning and structural characterization of a novel putative potassium channel-blocking toxin from the same sample of venom from the North African scorpion, Androctonus amoreuxi. The deduced precursor open-reading frame is composed of 59 amino acid residues that consists of a signal peptide of approximately 22 amino acid residues followed by a mature toxin of 37 amino acid residues. The mature toxin contains two functionally important residues (Lys(27) and Tyr(36)), constituting a functional dyad motif that may be critical for potassium channel-blocking activity that can be affirmed from structural homologs as occuring in the venoms from other species of Androctonus scorpions. Parallel proteomic/transcriptomic studies can thus be performed on the same scorpion venom sample without sacrifice of the donor animal. (c) 2004 Published by Elsevier Inc.