Stabilization of an intermolecular i-motif by lipid modification of cytosine-oligodeoxynucleotidesElectronic supplementary information (ESI) available. See DOI: 10.1039/c8ob00920a

This paper describes the stabilization of an intermolecular i-motif by lipophilic modification on the 3′-terminus of oligonucleotides. The hydrophobic aliphatic chain connected at the 3′-terminus of a trinucleotide (dC) 3 promoted the formation of an i-motif and significantly enhanced the quadruplex's stability. The impact of lipophilic modification on i-motif's thermal stability was studied by UV-thermal denaturation melting experiments and isothermal titration calorimetry. We found that alkyl chains containing more than 14 carbon atoms could elevate the i-motif structure's stability in a wide range of pH and concentrations. High stability of intermolecular i-motif structures in lipid-modified C-oligodeoxynucleotides.