Construction and structure studies of DNA-bipyridine complexes as versatile scaffolds for site-specific incorporation of metal ions into DNA

The facile construction of metal–DNA complexes using ‘Click’ reactions is reported here. A series of 2′-propargyl-modified DNA oligonucleotides were initially synthesized as structure scaffolds and were then modified through ‘Click’ reaction to incorporate a bipyridine ligand equipped with an azido group. These metal chelating ligands can be placed in the DNA context in site-specific fashion to provide versatile templates for binding various metal ions, which are exchangeable using a simple EDTA washing-and-filtration step. The constructed metal–DNA complexes were found to be thermally stable. Their structures were explored by solving a crystal structure of a propargyl-modified DNA duplex and installing the bipyridine ligands by molecular modeling and simulation. These metal–DNA complexes could have wide applications as novel organometallic catalysts, artificial ribonucleases, and potential metal delivery systems.