I am trying to develop a planar (two dimensional) lattice based framework to simulate ring (circular) DNA and proteins. To verify my model, I need to simulate real DNA and proteins. The base idea for my simulation is that the a DNA or protein molecule is simulated with minimum energy if the lattice is simulating is canonical or simplest form. I would like to know examples of real DNA or proteins which are circular and planar. Thanks in advance for your help.