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, B', within 20 ns. The gating charge (similar to 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 tatter with phosphomoieties of the lipid head groups appear to stabilize the kinetic state B'