A residue at the cytoplasmic entrance of BK-type channels regulating single-channel opening by its hydrophobicity.

ABSTRACT: Single large-conductance calcium-activated K(+) (BK) channels encoded by the mSlo gene usually have synchronous gating, but a Drosophila dSlo (A2/C2/E2/G5/10) splice variant (dSlo1A) exhibits very flickery openings. To probe this difference in gating, we constructed a mutant I323T. This channel exhibits four subconductance levels similar to those of dSlo1A. Rectification of the single-channel current-voltage relation of I323T decreased as [Ca(2+) ](in) increased from 10 to 300 microM. Mutagenesis suggests that the hydrophobicity of the residue at the position is important for the wild-type gating; i.e., increasing hydrophobicity prolongs open duration. Molecular dynamics simulation suggests that four hydrophobic pore-lining residues at position 323 of mSlo act cooperatively in a "shutter-l

SUBMITTER: Guo Z 

PROVIDER: S-EPMC2292367 | biostudies-literature | 2008 May

REPOSITORIES: biostudies-literature