Metal-ion-mediated base pairs in nucleic acids

Nucleic acids and their analogues raise more and more interest in research areas outside biology and biochemistry. The functionalization of these evolutionary optimized self-assembhng macromolecules with metal ions widens their applicability even further. Previous efforts to incorporate metal ions site-specifically into nucleic acids focused on the covalent attachment of appropriate ligands to either the sugar phosphate backbone or the nuclecibases. More recently, the use of metal-ion-mediated base pairs, i.e. the replacement of natural nucleobases by ligands, was suggested as an alternative means. This microreview discusses selected examples of metal-ion-mediated base pairs, including those that comprise unmodified natural nuclecibases, and describes possible applications for the resulting metal-modified nucleic acids. ((c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008).