Regensburg 2019 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 6: Poster I

BP 6.10: Poster

Montag, 1. April 2019, 17:30–19:30, Poster B2

Hofmeister series for RNA and metal cations: Binding affinities and kinetics and thermodynamics from all-atom molecular dynamics simulation — Sergio Cruz-León and •Nadine Schwierz — Department of Theoretical Biophysics, Max Planck Institute of Biophysics, Max-von-Laue-Str. 3, 60438 Frankfurt, Germany.

RNA folding and function is crucially governed by metal cations. In addition to valence and concentration, the ion type is decisive in processes like folding, or interaction with other molecules. In spite of its biological importance, unraveling the molecular mechanism of ion-specific effects from experiments is challenging due to their limited spatial and temporal resolution. To fill this gap, we combine all-atom molecular dynamics simulation and advanced sampling techniques, to gain insight into the microscopic interactions between an RNA dinucleotide and metal cations. Our results show ordering of the ions according to binding affinities and exchange kinetics. Particularly, direct and reversed Hofmeister series are found to hold true for the interaction with backbone and nucleobase, respectively. We further include the microscopic level of understanding into Poisson-Boltzmann theory to calculate ion competition constants for monovalent ions which agree well with recent experiments. This detailed description of metal cation-RNA interactions provides the molecular origin of ion-specific effects for cations and RNA, being a tool to boost the modeling of complex RNA-cation phenomena.