Figure 2. Munc18-1 binds to central sequences and the C-terminus of the synaptobrevin SNARE motif.
(A) 1H-15N HSQC spectra of 14.5 µM 15N-synaptobrevin(1-96) in the absence (black contours) and presence (red contours) of 14.5 µM Munc18-1. Selected cross-peaks that were particularly broadened by Munc18-1 binding are labeled. (B) Plots of the ratios of the intensities of the synaptobrevin(1-96) 1H-15N HSQC cross-peaks observed in the presence of Munc18-1 versus those observed in its absence, as a function of residue number. Intensities were measured only for well-resolved cross-peaks. Ratios were calculated from experiments performed with two separate samples and averaged. Note that the synaptobrevin SNARE motif spans approximately residues 29–91 (Sutton et al., 1998).
Figure 2—figure supplement 1. The Munc13-1 MUN domain binds to the C-terminus of the synaptobrevin SNARE motif but not to more central sequences.
(A) 1H-15N TROSY-HSQC spectra of 20 µM 15N-synaptobrevin(29-93) in the absence (black contours) and presence (red contours) of 16.5 µM Munc13-1 MUN domain. Selected cross-peaks that were particularly broadened as a result of MUN domain binding are labeled. (B) Plots of the ratios of the intensities of the synaptobrevin(29-93) 1H-15N TROSY-HSQC cross-peaks observed in the presence of Munc13-1 MUN domain versus those observed in its absence, as a function of residue number. Intensities were measured only for well-resolved cross-peaks.
Figure 2—figure supplement 2. Reproducibility of 1H-15N HSQC cross-peak intensities.
The plot shows the intensities (arbitrary units) from the 1H-15N HSQC cross-peaks of two separate samples of 14.5 µM 15N-synaptobrevin(1-96) in the presence of 14.5 µM Munc18-1. Intensities were measured only for well-resolved cross-peaks. There is one black bar and one orange bar for each residue, representing the measurements made in the two separate experiments.