Unlocking G-quadruplex: Effect of unlocked nucleic acid on G-quadruplex stability

► Effect of UNA modifications in a model quadruplex has been studied. ► UNA modifications cause structural transitions in the G- quadruplex studied. ► UNA in loop stabilizes G-quadruplex but in the stem it destabilizes the structure. ► All the sequences are stable at 37 °C. ► UNA confers greater biostability on the oligonucleotides.