Figure 2.

Increased stability of base pairs decreases overstretching hysteresis. Open squares show the increasing-force scan and solid stars show the decreasing-force scan. (A) Effects of NaCl concentration for stretching a λ-DNA: 150 mM (black), 300 mM (green, same DNA as black), and 1 M (red, a different DNA from black and green). (B) Effects of temperature for stretching λ-DNA: 24°C (black), 19°C (red). (C) Effects of sequence composition; GC-rich DNA (red) shows less hysteresis than AT-rich DNA (black). Extensions are scaled with their respective contour lengths.