Table 1. Binding of Bryostatin 1 and PDBu by the Munc13-1 C1 Domain and Its Mutant^a.

	Ki for bryostatin 1 (nM)			Kd for PDBu (nM)
lipid conditions	5:95 PS/PC	20:80 PS/PC	100:0 PS/PC	5:95 PS/PC	20:80 PS/PC	100:0 PS/PC
Munc13-1 FL			0.45 ± 0.04			7.09 ± 0.53
Munc 13-1 C1 WT	22.8 ± 1.8b	22.68 ± 0.54b	8.07 ± 0.90	82 ± 15	69.5 ± 4.8c	124 ± 13
Munc 13-1 C1 W22A mutant			54 ± 12			808.6 ± 8.1

^aThe bryostatin 1 binding affinity (K_i) and the PDBu binding affinity (K_d) were determined for the full-length (FL) Munc13-1 and the C1 domain of Munc13-1 wild type (WT) and its mutant under three different lipid conditions. Values represent the mean ± SEM from three independent experiments. One-way ANOVA, followed by Tukey’s post hoc test, was used for the analysis of statistical significance.

^bP < 0.001 compared to 100% PS in K_i for bryostatin 1.

^cP < 0.05 compared to 100% PS in K_d for PDBu.