Construction of Artificial DNAs Containing a Metal Complex-Type Base Pair

A number of strategies have been so far employed for modifying the periphery of DNA with metal complexes. However, little has been done to explore the DNA core . Recently, we envisioned the use of charged or uncharged metal complexes as replacement building blocks in the interior of the DNA helix. Replacement of the hydrogen-bonded base pairing of natural DNA by alternative base pairing modes is expected to lead not only to expansion of the genetic alphabet but also to novel DNA structures and functions based on the controlled and periodic spacing of the building blocks along the helix axis. This paper provides a summary of our recent progress devoted to the introduction of metal-assisted base pairs directed towards what we term the nano-assembly of metals into the DNA core . Specifically, we detail here syntheses of artificial /3-C-nucleosides bearing a chelator nucleobase (o-phenylenediamine, catechol, 2-aminophenol, pyridine, or hydroxypyridone , and so on), their metal coordination properties with metal ions, and the incorporation of these building blocks into DNA oligomers . The present results raise the appealing possibility that this approach could lead eventually to a novel molecular architecture-type approach to the nano-assembly of multi-metal arrays .