Referenced in: none

Automatically associated channels: Kv1.3

Title: Unusual binding mode of scorpion toxin BmKTX onto potassium channels relies on its distribution of acidic residues.

Authors: Zongyun Chen, Youtian Hu, Jun Hu, Weishan Yang, Jean-Marc Sabatier, Michel De Waard, Zhijian Cao, Wenxin Li, Song Han, Yingliang Wu

Journal, date & volume: Biochem. Biophys. Res. Commun., 2014 Apr 25 , 447, 70-6

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/24704423

Abstract
Besides classical scorpion toxin-potassium channel binding modes, novel modes remain unknown. Here, we report a novel binding mode of native toxin BmKTX towards Kv1.3 channel. The combined experimental and computational data indicated that BmKTX-D33H analog used the classical anti-parallel β-sheet domain as the channel-interacting interface together with the conserved channel pore-blocking Lys(26). However, the wild-type BmKTX was found to use Arg(23) rather than Lys(26) as the new pore-blocking residue, and mainly adopt the turn motif between the α-helix and antiparallel β-sheet domains to recognize Kv1.3 channel. Together, these findings not only reveal that scorpion toxin-potassium channel interaction modes are more diverse than thought, but also highlight the functional role of toxin acidic residues in mediating diverse toxin-potassium channel binding modes.