Silver-Mediated Double Helix: Structural Parameters for a Robust DNA Building Block

The DNA double helix is a versatile building block used in DNA nanotechnology. To potentiate the discovery of new DNA nanoscale assemblies, recently, silver cations have been introduced to pair DNA strands by base-Ag⁺-base bonding rather than by Watson-Crick pairing. In this work, we study the classical dynamics of a parallel silver-mediated homobase double helix and compare it to the dynamics of the antiparallel double helix. Our classical simulations show that only the parallel double helix is highly stable through the 100 ns simulation time. A new type of H-bond previously proposed by our collaboration and recently observed in crystal-determined helices drives the physicochemical stabilization. Compared to the natural B-DNA form, the metal-mediated helix has a contracted axial base pair rise and smaller numbers of base pairs per turn. These results open the path for the inclusion of this robust metal-mediated building block into new nanoscale DNA assemblies.