Regensburg 2019 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 9: Computational biophysics
BP 9.5: Vortrag
Dienstag, 2. April 2019, 10:45–11:00, H11
QM/MM free energy maps and nonadiabatic simulations for a photochemical reaction in DNA: cyclobutane thymine dimer — •Jesus I. Mendieta Moreno1, 2, Daniel G. Trabada2, Jesus Mendieta3, Paulino Gomez-Puertas3, and Jose Ortega2 — 1FZU of the CAS, Prague, Czequia — 2UAM, Madrid, Spain — 3CBMSO, Madrid, Spain
The absorption of ultraviolet radiation by DNA may result in harmful genetic lesions that affect DNA replication and transcription, ultimately causing mutations, cancer, and/or cell death. We analyze the most abundant photochemical reaction in DNA, the cyclobutane thymine dimer, using hybrid quantum mechanics/molecular mechanics (QM/MM) techniques and QM/MM nonadiabatic molecular dynamics. We find that, due to its double helix structure, DNA presents a free energy barrier between nonreactive and reactive conformations leading to the photolesion. Moreover, our nonadiabatic simulations show that most of the photoexcited reactive conformations return to standard B-DNA conformations after an ultrafast nonradiative decay to the ground state. This work highlights the importance of dynamical effects (free energy, excited-state dynamics) for the study of photo-chemical reactions in biological systems.
Jesús I. Mendieta-Moreno et al, Quantum Mechanics/Molecular Mechanics Free Energy Maps and Nonadiabatic Simulations for a Photochemical Reaction in DNA: Cyclobutane Thymine Dimer. J. Phys. Chem. Lett. 2016 7, 4391-4397.