Figure 3. Chemical structure of hERG channel blockers.

These ligands illustrate some aspects of the structural diversity of hERG blockers and have been shown to block hERG by binding to sites within the inner cavity of the channel. The structures illustrate the protonated states of nitrogen atoms at physiological pH, and the hydrogen bond acceptor (A) and donor (D) atoms. The structures of all ligands were obtained from ChemIDplus website, redrawn using Marvin Beans 4.0.5 (Chemaxon) and pK_A calculations for all ligands were measured at pH 7.2 using the plug-in within MarvinSketch. The authors are grateful to Dr Phill Stansfeld, University of Oxford, for the illustrations of chemical structure in this figure.