Fig. 4.
Effects of ionic strength on ssDNA flexibility. (a) Extracted persistence length, lP, vs. ionic strength ([NaCl] + [Tris buffer]) for (dT)30 (red circles), (dT)40 (purple circles), and (dT)50 (cyan circles). Solid red, purple, and cyan lines: respective fits to model, with constant, intrinsic persistence length
and electrostatic contribution
. Dotted lines: respective fits to model,
, where the electrostatic contribution varies as
. (b) Residuals plotted for fits in a. Fits were weighted by using error value averaged over all data points.