Probing the outer vestibule of a sodium channel voltage sensor.

  title={Probing the outer vestibule of a sodium channel voltage sensor.},
  author={Naibo Yang and Alfred L. George and Richard Horn},
  journal={Biophysical journal},
  volume={73 5},
The second and third basic residues of the S4 segment of domain 4 (D4:R2 and D4:R3) of the human skeletal muscle Na+ channel are known to be translocated from a cytoplasmic to an extracellular position during depolarization. Accessibilities of individual S4 residues were assayed by alteration of inactivation kinetics during modification of cysteine mutants by hydrophilic methanethiosulfonate reagents. The voltage dependences of the reaction rates are identical for extracellular application of… CONTINUE READING