A DNA Structure Containing AgI‐Mediated G:G and C:C Base Pairs

Metal‐mediated base pairs have been extensively utilized in many research fields, including genetic‐code extension, novel therapeutics development, and nanodevice design. Compared to other cations, AgI is more flexible in pairing with natural base pairs. Herein, we present a DNA structure containing two C‐AgI‐C pairs and the first reported G‐AgI‐G pair in a short 8mer DNA strand. This structure not only provides detailed insight into these AgI‐mediated base‐pairing patterns in DNA, but also represents the first nonhelical DNA structure driven by heavy‐metal ions, thus further contributing to the structural diversity of DNA. This unique complex structure is highly sequence‐dependent, thus implying functional potentials as a new DNA aptamer that can bind and recognize silver ions. These results not only advance our understanding of the interactions between AgI and nucleobases, but also provide a unique structural component for the rational design of new DNA nanodevices. A pretty pair: In a novel DNA structure containing G‐AgI‐G and C‐AgI‐C pairs, the DNA adopts an unusual nonhelical fold with sharp turns in each strand. In the crystal, many DNA molecules are tightly bound together through metallophilic attraction and hydrogen‐bonding interactions between the metallo base pairs. These results provided a useful structural basis for the rational design of new DNA nanodevices based on AgI‐mediated base pairs.