Supplementary Figure 9: FRET measurements revealed that the intramolecular interaction between C2A and C2B is not influenced by either Ca2+ or membranes.
From: Linker mutations reveal the complexity of synaptotagmin 1 action during synaptic transmission
(a) Representative emission spectra of AEDANS-labeled C2AB in 0.1 mM EGTA, 0.1 or 1 mM free Ca2+ with, or without, liposomes that harbored 25% PS; the labeled protein was excited at 295 nm. Peak 1 is the emission peak of two native Trp residues in C2B domain. Peak 2 is the emission peak of AEDANS conjugated to the C2A domain. As a control, unlabeled C2AB was analyzed in parallel (in EGTA, minus liposomes). (b) Scatter plot of peak 2 divided by peak 1, under each condition; plotted values represent the mean ± SEM. For each condition, 4–6 independent experiments were carried out. Statistical significance was determined using a bootstrap approach; no significant differences were observed (Supplementary Table 1).
