Fig. 3.

SMFS spectra recorded upon unfolding of BetpΔC45 recorded in buffer solution that enables transporter activation and substrate-binding. (A) Superimpositions of 95 F-D curves. Histograms show probability (B) and average forces (C) of fp detected at certain contour lengths. n gives the number of F-D curves superimposed. F-D curves were recorded in buffer condition (400 mM KCl, 100 mM NaCl, 5 mM betaine, 50 mM Tris-HCl, pH 7.5) at a pulling velocity of 100 nm/s. fp were marked with p-values of < 0.1 (*), < 0.05 (**), and < 0.01 (***) from T-student tests that show which of the fp changes compared to WT BetP (Fig. 1) were significant.