Fig. 3
From: Focused clamping of a single neuronal SNARE complex by complexin under high mechanical tension
Complexin promotes the linker-open state of neuronal SNARE complexes. a, c, d High-speed observations (1.2 kHz) of the conformational intermediates during the unzipping of a SNARE complex. The measured distributions of extensions (black lines displayed to the right of the traces) are overlaid with their identified Gaussian components color-coded green, magenta, orange, and gray from the lowest. Dotted areas are magnified on the right. The locations of the peaks are indicated with dashed lines of the same color and with numbers. b A model for the intermediate conformations of a SNARE complex with calculated values of extension. e Force-dependent shifts in extension distribution with the indicated Gaussian components. The color code is the same as in a–d. f Force-dependent equilibria among the three zippered conformations in the absence (upper) and presence (lower) of Cpx. Solid lines represent the fits to a three-state equilibrium model (Supplementary Note 5). Data are represented as mean ± s.d. of more than three measurements. g, i, j High-speed observations of the conformational intermediates during the zippering of a SNARE complex. The color code is the same as in a–f. h Comparisons of conformational equilibria during unzipping (upper; 10 → 14 pN) and zippering (lower; 16 → 14 pN) of a single SNARE complex. In all panels, vertical scale bars represent 20 nm. Horizontal scale bars represent 1 and 0.1 s (on left and right in a, c, d, g, i, j, respectively), and 10 nm (in e, h)
