Fig. 1.

Crystal structures of (a) the tetrameric KcsA (PDB: 1BL8) [105] and the monomers of (b) KvAP (1ORQ) [1] and (c) Kv1.2 (PDB: 3LUT) [5] to simplify the view of these large structures. The conductance domain is in gray, the voltage sensing domain of KvAP and Kv1.2 with 4 TM helices is in green. The hydrophilic interfacial regions are pale blue bands underlying the three structures. The electron density associated with partial occupancy of the K⁺ ions is shown in purple. These ions and the conductance domain provide an accurate picture of the bilayer normal for orienting these structures.