Large-conductance Ca²⁺- and voltage-gated K⁺ channels form and break interactions with membrane lipids during each gating cycle.

ABSTRACT: Membrane depolarization and intracellular Ca²⁺ promote activation of the large-conductance Ca²⁺- and voltage-gated (Slo1) big potassium (BK) channel. We examined the physical interactions that stabilize the closed and open conformations of the ion conduction gate of the human Slo1 channel using electrophysiological and computational approaches. The results show that the closed conformation is stabilized by intersubunit ion-ion interactions involving negative residues (E321 and E324) and positive residues (³²⁹RKK³³¹) at the cytoplasmic ends of the transmembrane S6 segments ("RKK ring"). When the channel gate is open, the RKK ring is broken and the positive residues instead make electrostatic interactions with nearby membrane lipid oxygen atoms. E3

SUBMITTER: Tian Y 

PROVIDER: S-EPMC6486743 | biostudies-literature | 2019 Apr

REPOSITORIES: biostudies-literature