Initial response of the potassium channel voltage sensor to a transmembrane potential.
Early transition events of the voltage sensor (VS) of Kv1.2 potassium channel embedded in a lipid membrane are triggered using full atomistic molecular dynamics (MD) simulations. When subject to an applied hyperpolarized transmembrane (TM) voltage, the VS undergoes conformational changes and reaches a stable kinetic intermediate state, beta', within 20 ns. The gating charge ( approximately 2e) associated with this fast transition results mainly from salt-bridge rearrangements involving negative charges in S2 and S3 and all but the two top residues R(294) and R(297) of S4. Interactions of the latter with phosphomoieties of the lipid head groups appear to stabilize the kinetic state beta'.
Treptow
Werner
W
Center for Molecular Modeling and Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Tarek
Mounir
M
Klein
Michael L
ML
D015640:Ion Channel Gating; D007700:Kinetics; D051663:Kv1.2 Potassium Channel / Q000737:chemistry*; D008051:Lipid Bilayers / Q000737:chemistry*; D008564:Membrane Potentials; D008958:Models, Molecular; D010713:Phosphatidylcholines / Q000737:chemistry; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D055672:Static Electricity; D013816:Thermodynamics
D051663:Kv1.2 Potassium Channel; D008051:Lipid Bilayers; D010713:Phosphatidylcholines; C028694:1-palmitoyl-2-oleoylphosphatidylcholine