Fig. 2. Sequence dependence of chain dynamics and internal friction in single-stranded nucleic acids.

a Distributions of relative donor (green contours) and acceptor fluorescence lifetimes (red contours) versus transfer efficiency of ssDNA and ssRNA from all detected fluorescence bursts (white points: average lifetime and efficiency) compared with predictions from analytical polymer models (analogous to Fig. 1e), the HCG (gray) and HCG_BioEn ensembles (cyan) for ssRNA and the reweighted polymer models (PM_BioEn: purple triangles) for the ssDNA. b Dye-to-dye distance distributions from HCG_BioEn ensembles (cyan) and reweighted polymer models (purple triangles) with root mean square end-to-end distance, R, indicated as vertical lines. c Representative normalized subpopulation-specific nsFCS measurements (color code as in Fig. 1) for dT₁₉ at different viscosities (uncertainties correspond to standard deviations of the solvent viscosities estimated from diffusion times using a calibration curve derived from FCS measurements, see Methods) with fluorescence correlation times, τ_cd (black lines, global fits; see Methods). d Solvent viscosity (η) dependence of chain reconfiguration times, τ_r, of ssNAs (color code according to distance distributions as shown in b) with linear fits (shaded bands: 95% confidence intervals). Values and error bars for ${\tau }_r$ at the viscosity of water are the mean and standard deviation, respectively, from three independent measurements. Values and error bars for ${\tau }_r$ at higher viscosities represent means and standard deviations from the values obtained based on four different distance distributions (GC, WLC, SAW-ν, HCG_BioEn). Source data are provided as a Source Data file.