Аннотация:Abstract DNA sequences comprising noncanonical 7‐deazaguanine ( 7C G) and canonical cytosine (C) are capable of forming Watson–Crick base pairs via hydrogen bonds as well as silver(I)‐mediated base pairs by coordination to central silver(I) ions. Duplexes I and II containing 7C G and C have been synthesized and characterized. The incorporation of silver(I) ions into these duplexes has been studied by means of temperature‐dependent UV spectroscopy, circular dichroism, and DFT calculations. The results suggest the formation of DNA molecules comprising contiguous metallated 7C G‐Ag I ‐C Watson–Crick base pairs that preserve the original B‐type conformation. Furthermore, additional studies performed on duplex III indicated that, in the presence of Ag I ions, 7C G–C and 7C A–T Watson–Crick base pairs ( 7C A, 7‐deazadenine; T, thymine) can be converted to metallated 7C G‐Ag I ‐C and 7C A‐Ag I ‐T base pairs inside the same DNA molecule whilst maintaining its initial double helix conformation. These findings are very important for the development of customized silver–DNA nanostructures based on a Watson–Crick complementarity pattern.
