Evidence for lateral mobility of voltage sensors in prokaryotic voltage-gated sodium channels.
Voltage-sensor domains (VSDs) in voltage-gated ion channels are thought to regulate the probability that a channel adopts an open conformation by moving vertically in the lipid bilayer. Here we characterized the movement of the VSDs of the prokaryotic voltage-gated sodium channel, NaChBac. Substitution of residue T110, which is located on the extracellular side of the fourth transmembrane helix of the VSD, by cysteine resulted in the formation of a disulfide bond between adjacent subunits in the channel. Our results suggest that T110 residues in VSDs of adjacent subunits can come into close proximity, implying that the VSDs can move laterally in the membrane and constitute a mechanism that regulates channel activity.
Nagura
Hitoshi
H
Department of Biophysics, Graduate School of Science, Kyoto University, Oiwake, Kitashirakawa, Sakyo-ku, Kyoto 606-8502, Japan.
Irie
Katsumasa
K
Imai
Tomoya
T
Shimomura
Takushi
T
Hige
Toshihide
T
Fujiyoshi
Yoshinori
Y
D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics; D002460:Cell Line; D003545:Cysteine / Q000737:chemistry; D006801:Humans; D009154:Mutation; D010084:Oxidation-Reduction; D055503:Protein Multimerization; D017433:Protein Structure, Secondary; D015222:Sodium Channels / Q000737:chemistry* / Q000235:genetics; D015032:Zinc / Q000737:chemistry
D001426:Bacterial Proteins; C443666:NaChBac protein, bacteria; D015222:Sodium Channels; D015032:Zinc; D003545:Cysteine