Fig. 6: Molecular mechanism of voltage-dependent gating in BK channel.
From: Structural basis of voltage-dependent gating in BK channels
a the voltage-dependent channel opening involves rotary motion of the gating charges (R2 and R3) on the S4 segment, which causes the positively charged groups of R2 to cross an electric field (hydrophobic gasket). This results in the cytoplasmic end of S4 moving inward and interacting with the non-S4 helices of the VSD, facilitating electromechanical coupling. b The process of electromechanical coupling is facilitated by the interaction between the VSD-CTD and hydrophobic (orange) and ionic interactions participate in open pore stabilization. c Canonical and non-canonical interactions transfer energy from sensors via S0’ → S4 → S5 → S6 in the TMD.
