I-Motif DNA structures upon electric field exposure: completing the map of induced genetic errors

Abstract

The architecture of DNA is not exclusively assembled with a sequence of Watson–Crick guanine–cytosine (GC) and adenine–thymine (AT) base pairs. On the contrary, recent experiments have detected G-quadruplex structures in G-islands, whereas C-rich regions are organized as intercalated motif (i-motif) structures. In the latter, several hemiprotonated–cytosine dimers are inserted in a large repetitive series. Previous computational characterizations of the impact of external electric fields on DNA’s mutations were focused on understanding GC, AT and G-quadruplex species. The present work provides a first assessment of the influence of intense fields onto the structure of i-motifs with the aim of reaching a more accurate prediction of the stability of DNA under the exposure of physics agents. The performed calculations demonstrate that i-motifs are particularly sensitive to the applied fields.