Figure 8.
smFRET trajectories (left column) and histograms (right column) for the 3′-tail-pdT15-Cy3/Cy5 substrate at low salt conditions (10 mM NaCl, with 6 mM MgCl2 and 10 mM Tris, pH 8.0). (A) 0.1 μM gp32; (B) 1 μM gp32. Cy3 fluorescence levels have been vertically displaced to clearly display the anti-correlated signal fluctuations. The red-shaded regions in the histograms show the probability distribution of background signals, which was determined from control measurements performed using biotin-Cy3 samples (see Supplementary Data).