Voltage-dependent conformational changes in human Ca(2+)- and voltage-activated K(+) channel, revealed by voltage-clamp fluorometry.

ABSTRACT: Large conductance voltage- and Ca(2+)-activated K(+) (BK(Ca)) channels regulate important physiological processes such as neurotransmitter release and vascular tone. BK(Ca) channels possess a voltage sensor mainly represented by the S4 transmembrane domain. Changes in membrane potential displace the voltage sensor, producing a conformational change that leads to channel opening. By site-directed fluorescent labeling of residues in the S3-S4 region and by using voltage clamp fluorometry, we have resolved the conformational changes the channel undergoes during activation. The voltage dependence of these conformational changes (detected as changes in fluorescence emission, fluorescence vs. voltage curves) always preceded the channel activation curves, as expected for protein rearrangements as

SUBMITTER: Savalli N 

PROVIDER: S-EPMC1567928 | biostudies-literature | 2006 Aug

REPOSITORIES: biostudies-literature