Molecular Stick-Slip Motion Revealed by Opening DNA with Piconewton Forces

Abstract

We have pulled apart the two strands of a DNA double helix. The forces measured during this process show a sequence specific variation on the piconewton scale. Opening two helical molecules with the same sequence from opposite sides gives two signatures which are not simply related by symmetry. In a theoretical model, this is explained as a molecular stick-slip motion which does not involve instabilities and is determined by the sequence.