Formation of i-motifs from acyclic ()-threoninol nucleic acids

Acyclic ( l )-threoninol nucleic acids (( l )-aTNA) containing poly-cytosines are prepared and investigated at various pH values, revealing the formation of a highly stable structure at lower pH that have the characteristics of an i-motif. Depending on the sequence, the aTNA forms inter-, bi- and intra-molecular i-motif structures. Pyrene was conjugated to aTNA sequences and both monomeric and excimer fluorescence were efficiently quenched by the i-motif structures and thus demonstrated that the aTNA i-motif can serve as a pH switch. Acyclic ( l )-threoninol nucleic acids (( l )-aTNA) containing poly-cytosines are prepared and investigated at various pH values, revealing the formation of a highly stable structure at lower pH that have the characteristics of an i-motif.