Caution is required in interpretation of mutations in the voltage sensing domain of voltage gated channels as evidence for gating mechanisms.

ABSTRACT: The gating mechanism of voltage sensitive ion channels is generally considered to be the motion of the S4 transmembrane segment of the voltage sensing domains (VSD). The primary supporting evidence came from R → C mutations on the S4 transmembrane segment of the VSD, followed by reaction with a methanethiosulfonate (MTS) reagent. The cys side chain is -SH (reactive form -S-); the arginine side chain is much larger, leaving space big enough to accommodate the MTS sulfonate head group. The cavity created by the mutation has space for up to seven more water molecules than were present in wild type, which could be displaced irreversibly by the MTS reagent. Our quantum calculations show there is major reorientation of three aromatic residues that face into the cavity in response to proton displ

SUBMITTER: Kariev AM 

PROVIDER: S-EPMC4307324 | biostudies-literature | 2015 Jan

REPOSITORIES: biostudies-literature