Zn2+-Dependent Peptide Nucleic Acids Probes.

Peptide nucleic acid (PNA) is a mimic of DNA which has excellent binding affinity and sequence specificity toward oligonucleotides. Researchers have synthesized PNA in which a Zn2+ chelating ligand is conjugated via an aromatic linker. Intercalation of the aromatic linker is regulated by the metal coordination to the ligand. It has been recently shown that unsymmetrically modified naphthalene diimide intercalates within PNA:DNA duplex and strongly stabilizes it. Therefore, this aromatic fragment was chosen as a linker between PNA and the ligand. As ligands, strong Zn2+ binders were selected: bis(picolyl)amine and 1,4,8,11-tetraazacyclotetradecane.