Duplex Pinching: A Structural Switch Suitable for Contractile DNA Nanoconstructions

A versatile role for guanine−guanine mismatches within DNA double helices such as the formation of specific, interhelical synaptic events has previously been reported. Here, we demonstrate that certain categories of guanine−guanine mismatches within double helices enable a different structural/conformational transition a reversible, intramolecular “pinching” of the duplex, initiated and reversed by the binding and dissociation of certain specific cations. Such a “pinching” transition should provide a valuable “contractile” feature to the design of new, DNA-based molecular motors and nanoconstructions.