Berlin 2018 – scientific programme

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BP: Fachverband Biologische Physik

BP 12: Computational Biophysics I

BP 12.7: Talk

Tuesday, March 13, 2018, 11:30–11:45, H 1058

On the nature of cytosine pairing in DNA structures — Miriam Kohagen and •Jens Smiatek — Institute for Computational Physics, University of Stuttgart, D-70569 Stuttgart, Germany

Besides protonated cytosine pairs, recent experimental results indicate that non-Watson-Crick DNA structures can also be stabilized by intercalated metal cations. Whereas Au+, Cu+ and Ag+ can be regarded as stabilizing agents, alkali metal ions like Na+, Li+ and K+ are known as destabilizers. In this article, we rationalize the experimentally observed behavior with the help of density functional theory calculations. Our results demonstrate the dominance of covalent electrostatic bonds, meaning that a significant amount of electron density has to be located on the cations in order to stabilize cytosine pairs. Further findings imply that mixed higher electron orbitals, in addition to a pronounced electronegativity of the cations, are of fundamental importance for the binding mechanism. The outcomes of our calculations establish a consistent theoretical framework to understand the experimentally observed behavior, which is also important to achieve a more detailed understanding of nucleobase pairing in general.