FIGURE 1.

Schematic illustrations of the labeling sites located in complexin and the SNARE complexes as well as the experimental system for smFRET assay. (a) Location of labeling sites on the SNARE complex, complexin, and complexin peptide. Synaptobrevin (VAMP) is blue, syntaxin is red, SNAP-25 (SN-25) is green, complexin is orange, and the binding-site peptide of complexin is pink. Residues that were mutated to cysteine for dye labeling are shown as yellow spheres along with their corresponding residue numbers (coordinates are taken from Chen et al. (5)). The unstructured C-terminal domain of complexin is indicated by the thin line. Position 45 corresponds to the labeling site at the N-terminus of the complexin peptide. Molecular graphics were generated using PyMOL (40). (b) Experimental setup for the detection of smFRET events.