Stuctural model and analysis of toxin BmKKx2 and its complex with hERG channel. (A-B) The distribution of functional residues and differential residues between BmKKx2 and BeKm-1. (A) BmKKx2, (B) BeKm-1. (C) The spatial orientation of hERG channel turrets and toxin BmKKx2 in their complex structural. (D) Interaction details between hERG channel Ser 631 residues and toxin residues.