TABLE 1.

Energy barrier parameters of the fusion process for egg PC bilayers in the absence or presence of SNAREs in the specified combinations

	Energy barrier parameters
Bilayers	γ (Å)	k° (s−1)
SNARE-free versus SNARE-free	0.5	5.52
v- versus t-SNAREs	1.2	19.3
SNARE-free versus t-SNAREs	0.52	5.67
v- versus t-SNAREs w/cd-VAMP	0.65	6

Fusion was generated by compressing the bilayers that were present on the opposite hydrophilic substrates, the glass dish, and microbead attached to the AFM tip. The parameters were derived using the above model. Notice the >2-fold increase in the barrier width and ∼4-fold increase in the fusion rate when v- and t-SNARE proteins existed in the bilayers. See Fig. 3 for an interpretation of these parameters in terms of the energetics of the fusion reaction.