FIGURE 2.

Munc18-1 mutants have reduced binding to Syntaxin1a. A, Munc18-1 representation showing the locations of the F115E, E132A, and F115E/E132A mutations. B, Munc18-1 (WT and mutant) binding to Sx1a-His tethered to Co²⁺-affinity beads was analyzed by Coomassie-stained SDS-PAGE. Munc18-1 mutant binding to Sx1a was reduced compared with Munc18-1-WT. C, Munc18-1 (WT and mutant) binding to Sx1a tethered to Co²⁺-affinity beads was quantified and compared (n = 3). D, overlaid circular dichroism spectra measured for purified Munc18-1-WT (♦), Munc18-1-F115E (■), Munc18-1-E132A (▲), and Munc18-1-F115E/E132A (♦) proteins.