Figure 5.

Energetics of syb2 tilting movement in the membrane. (A–C) Harmonic potentials were applied to the ST group in the kinked state (A), generating directional movement through the hydrophobic core (B) to the extravesicular membrane-water interface (C). (D) The change of the ST group position is accompanied by a corresponding change in the TM domain tilt angle. (E) The free-energy profile constructed from the umbrella simulations (Table S2 and Fig. S2) shows a maximum when the C-terminus is located in the membrane center (black dots with error bars). The energy barrier is lowered to ∼3 k_BT when an 80 pN force is applied in the z direction (dashed line).