Fig. 1

Schematic cross-section of a VGIC with the four units (I-IV) in symmetrical positions around the channel pore. Each unit consists of six parallel α-helices/subunits (S1-S6). The voltage-sensors of the VGIC are the four S4 positively charged helices ( +) one in each unit. The S4 are the closest to the pore-forming S5-S6 helices having less than 1 nm distance from the pore (modified from⁷⁴).