Synthetic Oligonucleotide Modifications for the Investigation of Charge Transfer and Migration Processes in DNA

Abstract

With respect to the biological role during DNA damaging and to potential applications in DNA chip and nanotechnology, the DNA-mediated charge transfer phenomena attracted a lot of attention in the scientific community during the last 15 years. Most research groups have focused their work on the photochemically or photophysically induced oxidation or reduction of DNA using different charge donors. Organic and inorganic intercalators which were covalently attached to oligonucleotides have been employed. Using these DNA systems, a systematic measurement of the distance dependence and the base sequence dependence of the charge transfer processes became possible. This review gives a short overview about the existing photochemical donor-acceptor assays, and, more importantly, focuses on the preparative aspects of the different synthetic oligonucleotide modifications which were developed and applied by the different research groups in order to prepare suitable DNA assays for the studies of charge transfer chemistry. In many cases, DNA base or sugar modifications were introduced via automated solid-phase synthetic methods using the corresponding phosphoramidites as DNA building blocks. Alternatively, DNA modifications can be introduced by solid-phase methods which are applied during or after the automated solid-phase synthesis. It is shown that both methods are suitable for the design and preparation of interesting DNA assays. Keywords: Oligonucleotide, nanotechnology, DNA-mediated charge, automated solid-phase synthetic, DNA assays