README for Figure 4A

*** This file contains the raw data obtained from magnetic tweezers experiments shown in Figure 4A of:
Article: Modulation of archaean hypernucleosome structure and stability by Mg2+
Authors: Ilias Zarguit, Marc K. M. Cajili, Bert van Erp, Samuel Schwab, Nico van der Vis, Marianne Bakker, John van Noort, and Remus T. Dame
Corresponding author: rtdame@chem.leidenuniv.nl

Legend Figure 4: Mg2+ increases the compaction of HTkB fibers. A) Force extension curves and fits of HTkB hypernucleosome in the absence (gstack=2.85 kBT, gwrap=3.67 kBT, stiffness=0.51 pN/nm and angle=10.23°) and the presence of 2 mM Mg2+ ions (gstack=4.24 kBT, gwrap=6.49 kBT, stiffness=0.91 pN/nm and angle=11.61°), as indicated. The force required to reach extension of DNA, depicted by the dashed grey line, is higher in the presence of Mg2+ ions than in the absence of Mg2+ ions, representing a more stable hypernucleosome complex. This can be directly attributed to the Mg2+ ions. B-F) The histograms of stacking energy, wrapping energy, stiffness, bending angle, and number of bound dimers of HTkB in the absence and the presence of Mg2+ ions. The histograms were fitted with a normal distribution. The mean and standard error of mean of all fit parameters can be found in Table 2.
 
*** The data was obtained using magnetic tweezers as described in the associated article.

*** Columns show F (Force in pN) and z (Distance in micrometer) of HTkB hypernucleosomes in the absence (No Mg) and presence of 2 mM Mg2+ (Mg). 

