Extended Data Fig. 6: Implicit solvent simulations of DNA rotation.

a, Simulation system consisting of a rigid body representation of a DNA duplex surrounded by point-like particles representing potassium (red) and chloride (teal) ions. Two grid-based potentials prescribe the interactions between the DNA duplex and the ions, a 1 kcal mol^–1 iso-surface for DNA–potassium potential is shown in grey. The DNA duplex is effectively infinite under the periodic boundary conditions. The centre of mass of the duplex is harmonically restrained to prevent translation. A 100 mV/nm electric field is applied to the ions. b, Rotation angle as a function of simulations time for implicit solvent and all-atom simulations of DNA rotation under a 100 mV/nm electric field. The all-atom trace is from Fig. 1b. c, Average rotation rate versus electric field strength obtained from implicit solvent and all-atom simulations. The all-atom data are from Fig. 1c. d, Distributions of instantaneous torques, sampled every 2.4 ps and averaged over 5 ns blocks. A vertical solid line depicts the mean of each distribution. The effective torque was measured by preventing DNA rotation using a harmonic dihedral angle potential. The all-atom data are from Fig. 2c.