(a) View of a hypothetical Kv-type K+ channel from the extracellular side of the membrane, showing the central pore-forming region, S5-P-S6, modeled by the structure of KcsA, surrounded by a voltage-gating domain of unknown structure, composed of S1-S4. Reproduced with permission from . (b) Diagram of a typical K+ channel, showing the outward movement of the voltage-sensing transmembrane segment S4 concomitant with channel opening. Reproduced with permission from .
Miller Genome Biology 2000 1:reviews0004.1 doi:10.1186/gb-2000-1-4-reviews0004