FIGURE 1.

Model for SNARE-promoted membrane fusion. A trans complex is formed by synaptobrevin and SNAP-25 (blue), the H3 helix of syntaxin (cyan), a linker region (red), the transmembrane (TM) domains (tilted rectangles) of syntaxin (yellow), and synaptobrevin (magenta), which exerts mechanical force onto the vesicle (v) and the target (t) membrane and pulls them toward each other. The H3 helix tilt θ (pink) is studied in molecular dynamics simulations; the brown box marks the simulation system. The hydrophobic regions of the two membranes are colored green, their polar regions dark green.