FIGURE 3.

Effect of αS on SNARE-dependent membrane fusion is mainly on docking with little influence on the dynamics of bilayer merger. (A) Analysis of the bilayer merger dynamics with twice purified αS. The number of merger events at various αS concentrations are normalized with respect to events without αS. The dashed line represents the membrane merger activity of SNAREs without αS. (B) Analysis of the bilayer merger efficiency of twice purified αS. The efficiency is calculated as the number of merger events divided by the number of docking events. (C) Instant merger vs. delayed merger. Instant merger events display lipid-diffusion in under 20 ms and delayed merger events are any that take longer than 20 ms. (D) Representative cumulative plot of bilayer merger events with twice purified αS. The red line is the double exponential fit to the data of merger events. (E) Plot of time constants for instant merger events. (F) Plot of time constants for delayed merger events. The total of 1,247 merger events from 82 independent recording were included in the fitting analysis.