title: Theoretical study of excess electron attachment dynamics to the guanine-cytosine base pair: electronic structure calculations and ring-polymer molecular dynamics simulations.
abstract: Electron attachment dynamics to the guanine (G)-cytosine (C) base pair has been studied from a theoretical viewpoint. The BH&HLYP-level calculations show that the dipole-bound planar (G-C)(-) base pair anion can convert into the nonplanar valence-bound anion with a relatively small barrier. This nonplanar valence-bound anion can further convert into a more stable form via proton-transfer through the N-H···N hydrogen-bond from the guanine to cytosine moiety. This excess electron induced proton-transfer process has been studied using quantized ring-polymer molecular dynamics simulations (RPMD) on an interpolated potential energy surface developed on the basis of the B3LYP-level calculations. We compare the RPMD results to the results of classical MD simulations and found that proton-transfer more effectively occurs in quantum RPMD simulations. Both vibrational quantization and corner-cutting mechanism are playing important roles in this proton-transfer process. We have also analyzed the correlation between the proton-transfer motion and other vibrational motions including ring-ring deformation motions using the reactive RPMD trajectories.
authors.affiliation: Department of Chemistry, Saitama University , 255 Shimo-Okubo, Sakura-ku, Saitama City, Saitama 338-8570, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Sugioka
authors.forename: Takehiro
authors.initials: T
authors.lastname: Yoshikawa
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Takayanagi
mesh_terms: D020029:Base Pairing; D003596:Cytosine / Q000737:chemistry*; D004583:Electrons; D006147:Guanine / Q000737:chemistry*; D056004:Molecular Dynamics Simulation; D011522:Protons; D011789:Quantum Theory
chemical_list: D011522:Protons; D006147:Guanine; D003596:Cytosine