P. P. Kanevska and S. N. Volkov
Bogolyubov Institute for Theoretical Physics of the National Academy of Sciences of Ukraine, Kyiv, Ukraine
snvolkov [at] bitp.kiev.ua
Abstract
Our study introduces a model of DNA macromolecule deformation, which integrates both external and internal deformation components with their interrelations. The external deformation includes the twist and stretch of the DNA double helix, while the internal deformation involves the relative shift of base pairs within the double helix. The model incorporates the coupling between the twist and stretch of the double helix and with its internal restructuring. The model reveals counterintuitive dynamics: under stretching forces, the DNA double helix can exhibit increasing in twist up to a critical force. Over this force, the double helix behaves more like a conventional filament, showing untwisting in response to stretching. These findings highlight the significant impact of coupling between internal and external components on the mechanical behaviour of the double helix when subjected to forces lower of the critical point. The agreement of our model results with experimental data also confirms its accuracy and applicability.
Keywords: DNA mechanics, twist-stretch coupling, molecular modelling, structural dynamics, biophysics
Acknowledgement: I would like to express my gratitude to the University of Exeter for the opportunity to conduct research as an Honorary member. Additionally, I would like to acknowledge the support from the British Academy and Cara (the Council for At-Risk Academics) under the ‘Researchers at Risk’ programme, which is funded primarily by the UK Government.