A Novel Ag^I -DNA Rod Comprising a One-Dimensional Array of 11 Silver Ions within a Double Helical Structure

DNA/RNA duplexes containing metal-ion-mediated base pairs (metallo-base pairs) have potential applications in developing nucleic acid-based nanodevices and genetic code expansion. Many metallo-base pairs are formed within duplexes stabilized by Watson-Crick base pairs. Recently, the crystal structure of an Ag^I -DNA nanowire with an uninterrupted one-dimensional silver array was determined. Here, we present a new DNA helical wire, the "Ag^I -DNA rod", containing an uninterrupted array of 11 Ag^I ions. The Ag^I -DNA rod consisted of only C-Ag^I -C, G-Ag^I -G, G-Ag^I -5-bromouracil (^Br U), and ^Br U-Ag^I -^Br U metallo base pairs, with no Watson-Crick pairs. The Ag^I -DNA rods were connected by non-canonical G-G pairs in crystals. Notably, data from our absorbance, circular dichroism, nuclear magnetic resonance, and mass spectrometry analyses suggested that the Ag^I -DNA rods formed in solution, as well as within crystals.