TABLE 1.

Thermodynamic parameters of the interaction of synaptobrevin 2 mutants and different R-SNARE homologs with the neuronal ΔN complex measured by ITC at 25 °C

The experimental ITC data are shown in Figs. 2D and 5B. No heat changes were detected when the SNARE motifs of tomosyn or of Ykt6 were mixed with the ΔN complex (SyxH3·SNAP-25·Syb49–96). For comparison, the thermodynamic parameters for wild-type synaptobrevin 2 (12) and of three additional alanine layer mutations (19) are given as well.

Syringe	Kd	ΔH	−TΔS	ΔG	N
	nm	kcal mol−1	kcal mol−1	kcal mol−1
Syb1–96a	2.1 ± 0.6	−29.9 ± 0.3	18.1	−11.8	1.05
Syb1–96I45A	0.9 ± 0.4	−29.5 ± 0.3	17.2	−12.3	0.98
Syb1–96M46A	7.2 ± 1.4	−24.7 ± 0.2	13.6	−11.1	0.98
Syb1–96I45A,M46A	344.8 ± 44.7	−15.7 ± 0.4	6.9	−8.8	0.97
Syb1–96N49A,V50A	8.8 ± 1.6	−22.6 ± 0.2	11.6	−11.0	0.98
Endobrevin	0.8 ± 0.8	−21.3 ± 0.4	8.9	−12.4	0.99
VAMP4	1.1 ± 0.6	−15.3 ± 0.2	3.1	−12.2	1.04
Sec22	21.2 ± 8.2	−7.2 ± 0.2	−3.3	−10.5	1.05
Syb1–96F77Ab	0.8 ± 0.4	−18.8 ± 0.2	6.4	−12.4	0.99
Syb1–96L32A,T35Ab	44.1 ± 12.3	−16.6 ± 0.4	6.5	−10.1	1.01
Syb1–96V39A,V42Ab	8.4 ± 2.8	−23.4 ± 0.4	12.3	−11.1	1.02

^a Thermodynamic parameters for wild-type synaptobrevin 2.

^b Thermodynamic parameters for three additional alanine layer mutations.