Modulation of i-motif thermodynamic stability by the introduction of UNA (unlocked nucleic acid) monomers

The influence of acyclic RNA derivatives, UNA (unlocked nucleic acid) monomers, on i-DNA thermodynamic stability has been investigated. The 22 nt human telomeric fragment was chosen as the model sequence for stability studies. UNA monomers modulate i-motif stability in a position-depending manner. The largest destabilization is observed for position C14, while UNA placed in position A12 causes significant increase of i-DNA thermodynamic stability. CD curves of UNA-modified variants imply no structural changes relative to the native i-motif.