Critical torque for kink formation in double-stranded DNA
Biological Physics, Nonlinear Dynamics, Soft Matter, Molecular Spring
We measure the bending energy of double-stranded DNA in the nonlinear (sharply bent) regime. The measurements are obtained from the melting curves of stressed DNA ring molecules. The nonlinear elastic behavior is captured by a single parameter: the critical torque τc at which the molecule develops a kink. In this regime, the elastic energy is linear in the kink angle. This phenomenology is the same as for the previously reported case of nicked DNA. For the sequences examined, we find τc=31 pN×nm. This critical torque corresponds to a characteristic energy scale (π/2)τc=12 kT room relevant for molecular biology processes associated with DNA bending.
Qu, H., Wang, Y., Tseng, C., & Zocchi, G. (2011). Critical torque for kink formation in double-stranded DNA. Physics Faculty Publications and Presentations., 1 (2), 21008. https://doi.org/https://doi.org/10.1103/PhysRevX.1.021008