Fig. 2: Illumination-intensity-dependent changes in FRET efficiency.
From: Recovering true FRET efficiencies from smFRET investigations requires triplet state mitigation
a, Schematic of the 21-nucleotide DNA duplex labeled with a donor dye at the 5′ terminus of one strand and an acceptor dye labeled at an internal position of the complementary strand separated by 14 nucleotides. b, Representative single-molecule fluorescence and smFRET trace of a donor- and acceptor-labeled DNA duplex. c–f, Three-dimensional population FRET histograms (contour plots) (c,e) and corresponding population FRET histograms (d,f) of Cy3–Cy5 and LD555–LD655 FRET pairs attached to the DNA duplex at various illumination intensities, respectively. All the data were collected in deoxygenated imaging buffers in the absence of any exogenous solution additives (photoprotective agents) at 100 ms time resolution using a custom-built TIRF imaging platform51. The data at 3.60 kW cm−2 were collected at 5 ms time resolution.
