Figure 1.
The recurrence effect in single-molecule FRET experiments of freely diffusing molecules is clearly visible as clustering of photon bursts in binned time traces (a,b) (donor signal in green, acceptor signal in red, 1 ms binning). Points indicate the positions and the numbers of photon counts of identified bursts. The clustering is also the origin of fluorescence intensity correlation on time scales greater than the mean diffusion time (~1ms) through the confocal volume (c). Data were measured on freely diffusing FRET-labeled CspTm in 1.1 M GdmCl.