Energetics of pore opening in a voltage-gated K(+) channel.
Voltage-dependent gating in K(+) channels results from the mechanical coupling of voltage sensor movements to pore opening. We used single and double mutations in the pore of the Shaker K(+) channel to analyze a late concerted pore opening transition and interpreted the results in the context of known K(+) channel structures. Gating sensitive mutations are located at mechanistically informative regions of the pore and are coupled energetically across distances up to 15 A. We propose that the pore is intrinsically more stable when closed, and that to open the pore the voltage sensors must exert positive work by applying an outward lateral force near the inner helix bundle.
Yifrach
Ofer
O
Howard Hughes Medical Institute, Laboratory of Molecular Neurobiology and Biophysics, Rockefeller University, New York, NY 10021, USA.
MacKinnon
Roderick
R
D019943:Amino Acid Substitution; D000818:Animals; D008564:Membrane Potentials; D008958:Models, Molecular; D015221:Potassium Channels / Q000235:genetics / Q000502:physiology*; D011487:Protein Conformation; D051637:Shaker Superfamily of Potassium Channels; D014981:Xenopus
D015221:Potassium Channels; D051637:Shaker Superfamily of Potassium Channels