The influence of the DNA torque on the dynamics of transcription bubbles in plasmid PTTQ18

•The movement of transcription bubbles in plasmid PTTQ18 is simulated numerically.•The DNA torque impacts the bubble trajectories.•The stationary bubbles velocity does not depend on their initial velocity. In this work, we study numerically the influence of the DNA torque on the movement of transcription bubbles in the potential field formed by the sequence of plasmid PTTQ18. To imitate the movement, we apply a modified sine-Gordon equation with the two additional terms that describe the effects of dissipation and the action of the DNA torsion torque, and with the coefficients that depend on the sequence of bases. We obtain the trajectories of the transcription bubbles and investigate the dependence of the trajectories on the initial bubble velocity and the DNA torsion torque. It is shown that not the initial bubble velocity but the DNA torsion torque governs the trajectories of the transcription bubbles. [Display omitted]