Dresden 2026 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 22: Statistical Physics of Biological Systems II (joint session DY/BP)

BP 22.3: Vortrag

Mittwoch, 11. März 2026, 15:45–16:00, ZEU/0114

Impact of cytosine methylation on the diffusion of charges along DNA: a quantum perspective — •Mirko Rossini, Dennis Herb, Paul Raschke, and Joachim Ankerhold — Institute for Complex Quantum Systems, University of Ulm, Ulm, Germany

We develop a coarse-grained tight-binding (TB) framework that treats electrons and holes on equal footing. TB parameters, required to characterize the model, are derived from an ab-initio molecular scheme (linear-combination-of-atomicorbitals (LCAO)) that includes all valence orbitals. Simulations address unmethylated vs. methylated CpG-rich and regulatory sequences sensible to DNA methylation, enabling us to investigate the impact methylation has on the charge diffusion along models of critical relevance in epigenetics and shedding new light on possible undiscovered mechanisms for epigenetic regulation in cells.

Methylation substantially lowers cytosine charge energies (~150 meV) while leaving the opposite guanine nearly unchanged (<20 meV), thereby introducing site-selective energetic shifts that redesign diffusion pathways. Statistical investigations, such as time-averaged populations and Inverse Partecipation Ratio (IPR) analyses, show enhanced electron localization at methylated cytosines, contrasted by increased hole delocalization: these dual trends suppress electron-hole co-localization (localization at same sites) and reduce recombination probability, leading to higher trapping times of excess charges along the DNA. Consistently, modelled excitations lifetimes increase upon cytosine methylation.

Keywords: DNA; Quantum; Methylation; Tight-Binding