FIGURE 3:

YHRD mutations increase the distance between the C2 domains of syt-1. (A) AFM images of 3×C2AB and 3×C2AB-YHRD; dumbbell-like structures (doublets) were more common in the 3×C2AB-YHRD than 3×C2AB. (B) Gaussian fits of frequency distributions of maximum linear dimensions of 3×C2AB and 3×C2AB-YHRD. The 3× mutant was used to uncover length differences resulting from substitution of YHRD, as changes in the length of WT C2AB background could not be detected by AFM (unpublished data). The peaks of the distributions ± SEM are indicated; p < 0.001. n = 248 for both samples. Scale bar: 50 nm; color-height scale: 0–2 nm.