Diffusion of concentrated DNA rings undergoing dynamic concatenation

Topoisomerases can cleave, twist, untwist and reconnect ring DNA polymers to enable diverse biological processes including DNA replication and repair, as well as the formation of concatenated structures such as kinetoplasts. When DNA rings are highly overlapping, these topological operations can dramatically alter their diffusion and conformations. Here, we use single-molecule conformational tracking to characterize the non-equilibrium transport and conformational dynamics of highly concentrated DNA rings undergoing dynamic concatenation via the linking and unlinking action of Topoisomerase II. We show that these toplogically-active Olympic rings can exhibit both enhanced and halted diffusivity depending on the Topoisomerase digestion rate and DNA concentration. Future work will build on this bio-inspired platform by incorporating additional enzymes that fragment and ligate DNA for in situ alteration of DNA length.