Contractile rings formed from cytoskeletal filaments mediate the division of cells. The reverse-engineering of synthetic contractile rings could shed light on fundamental physical principles of the ring self-assembly and dynamics independent of the natural protein-based compounds. Here, we engineer DNA nanotubes and crosslink them with a synthetic peptide-functionalized star-PEG construct. The star-PEG construct induces the formation of DNA nanotube bundles composed of several tens of individual DNA nanotubes. Importantly, the DNA nanotube bundles curve into closed micron-scale DNA rings in a high-yield one-pot self-assembly process resulting in several thousand rings per microliter. The crosslinked DNA rings can undergo contraction to less than half of their initial diameter by two distinct mechanisms, triggered by increasing molecular crowding or temperature. DNA-based contractile rings expand the toolbox of DNA nanotechnology and could be a future element of an artificial division machinery in synthetic cells.
