The elastic energy of sharply bent nicked DNA
DNA springs, protein-DNA chimeras, biomolecules, equilibrium deformations, polymer physics
We obtain measurements of the elastic energy of short (18–30 bp) molecules of ds DNA constrained into a sharply bent conformation, using a thermodynamic method with the DNA in solution. We consider the case where there is one nick in the ds DNA, and find that the system develops a kink at a critical torque τc≈27 pN×nm. In this regime the elastic energy is linear in the end-to-end distance (EED). For smaller torques the DNA is smoothly bent and described by the worm-like–chain energy, which is also approximately linear in the EED, but with a different slope. Thus we access both the high and low elastic energy regimes, and the transition between the two.
Qu, H., Tseng, C., Wang, Y., Levine, A. J., & Zocchi, G. (2010). The elastic energy of sharply bent nicked DNA. Physics Faculty Publications and Presentations., 90 (1), 18003. https://doi.org/https://doi.org/10.1209/0295-5075/90/18003