Intrinsic ligand as a key element in hERG channel gating. (A) Ribbon representation of the full-length structure of hERG channels (PDB accession no. 5VA2) viewed from the side and down the pore of the channel. The intrinsic ligand is shown in a space-filling model. The figures were prepared using PyMol (Schrodinger, LLC). (B) Hypothesized pulling/rotation motion regulated by the intrinsic ligand. Only two opposing subunits are shown for clarity. The color coding scheme in A and B is the same as in Fig. 1.