Fig. 4: The stable function of CpxI NTD and Cpx CH domain can slightly inhibit the assembly of C-terminal of SNARE complex.

In the presence of 8 μM AH-CH domain (26-83 aa), 38 of 66 (57.5%) dynamic molecules changed their state after the addition of the CpxI fragment. a Extension-time trajectories and b zoom-in view of the traces in the dashed rectangle suggest that 66% of them was stabilized to C-terminal stabilized state after the addition of 8 μM AH-CH domain (26-83 aa) in real time, 31.5% of SNARE complex were locked at the C-terminal blocked state after (red) the addition of 8 μM AH-CH domain. For the addition of a shorter fragment of CH domain (8 μM 48-73 aa), 26 of 32 (81%) dynamic molecules changed their state in the presence of CpxI fragment. c FEC curve, black: pulling before the addition of CpxI, gray: relaxing before the addition of Cpx, red: pulling after the addition of CpxI, cyan: relaxing after the addition of CpxI. d Summary of the distribution of the different kind of signals introduced by fragments of 1-83 aa or 26-83 aa. e FECs of single SNARE complexes in the presence of merely CH domain. 96% of the SNARE complex were locked to the C-terminal blocked state after (red) the addition of CpxI CH domain. The paired t-test was applied to evaluate the statistics with a p-value of *p < 0.04, **p < 0.002, and ***p < 10^-8.