Molecular Docking Simulation of Short-Chain Four Disulphide Bridged Scorpion Toxins with Structural Model of Human Voltage-Gated Potassium Ion Channel Kv1.3

We report structural model of the human voltage-gated potassium ion channel Kv1.3 obtained based on the crystallographic structure of KcsA by homology modeling. Molecular docking simulations were performed between the model structure of Kv1.3 channel with three short-chain four disulphide bridged scorpion toxins HsTX1 from the venom of Heterometrus spinnifer (Scorpionidae), maurotoxin (MTX) from Scorpiomaurus palmatus and Pandinus toxin 1(Pi1) from Pandinus imperator which belongs to the -KTx6 subfamily. By integrating the homology modeling and docking simulations we obtained the three dimensional structures of toxin-channel complexes. The final docked complexes were then subject to minimization with CHARMM force field and investigated key interacting residues, electrostatic interaction energies, binding free energies, disulphide bridge pairing determination, folding pattern, hydrogen bond formation, hydrophobic contacts and flexibilities between selected scorpion toxins to the Kv1.3 channel.