Fig. 3: Force dependency of promoter binding of RNAP III initiation factors at a canonical RNAP III promoter. | Nature Communications

Fig. 3: Force dependency of promoter binding of RNAP III initiation factors at a canonical RNAP III promoter.

From: DNA origami-based single-molecule force spectroscopy elucidates RNA Polymerase III pre-initiation complex stability

Fig. 3

a Structural model (PDB: 5N9G) of the U6 snRNA promoter (U6, dark grey) in an unbent conformation and the bent state bound by TBP (yellow), TBP/Brf2 (orange) and TBP/Brf2/Bdp1 (red). b Single-molecule FRET measurements on diffusing molecules monitor TBP-induced DNA bending after the addition of TBP (20 nM), TBP/Brf2 (20 nM) or TBP/Brf2/Bdp1 (20 nM) to the U6 DNA origami force clamps at increasing forces (0, 2.6 and 6.6 pN). FRET efficiency histograms showing the relative distribution between the unbent DNA state (low FRET state, E = 0.19, grey) and TBP-induced bent states in the absence and presence of additional initiation factors (high FRET population, E = 0.39 (TBP only, yellow), E = 0.75 (TBP/Brf2, orange), E = 0.76 (TBP/Brf2/Bdp1, red)). Low and high FRET populations were fitted with a Gaussian distribution. Each measurement was carried out at least three times. See also Supplementary Fig. 5 and Supplementary Table 2.

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