Nucleic acids are suitable scaffolds for the precise arrangement of different kinds
of artificial functionalities inside or along the double helix. In this account, we
summarize our synthetic efforts over the last ten years to modify DNA chemically with
organic chromophores, fluorescent probes, and metal-ion ligands. We used three different
approaches: (i) replacement of DNA bases (substitutes/surrogates), (ii) modifications
of DNA bases (mainly 2′-deoxyuridine), and (iii) sugar modifications at the 2′-position.
The first two types of modifications were achieved mainly by the DNA building block
approach, whereas the latter type is based on postsynthetic methodologies. The different
synthetic concepts are described and the influence of representative modifications
on the melting temperature is compared.
Key words
chromophore - oligonucleotide - building block - fluorescence - energy transfer