Data from: Simulation assisted analysis of the intrinsic stiffness for short DNA molecules imaged with scanning atomic force microscopy

Studying the mechanical properties of short segments of dsDNA can provide
insight into various biophysical phenomena, from DNA looping to the
organization of nucleosomes. Scanning atomic force microscopy (AFM) is
able to acquire images of single DNA molecules with near-basepair
resolution. From many images, one may use equilibrium statistical
mechanics to quantify the intrinsic stiffness (or persistence length) of
the DNA. However, this approach is highly dependent upon both the correct
microscopic polymer model and a correct image analysis of DNA contours.
These complications have led to significant debate over the flexibility of
dsDNA at short length scales. We first show how to extract accurate
measures of DNA contour lengths by calibrating to DNA traces of simulated
AFM data. After this calibration, we show that DNA adsorbed on an
aminopropyl-mica surface behaves as a worm-like chain (WLC) for contour
lengths as small as ~20 nm. We also show that a DNA binding protein can
modify the mechanics of the DNA from that of a WLC.