Hello I have some interesting DNA structures I would like help with . The duplexes are stacked in the crystal head to head and tail to tail. This creates an interesting situation where an adenine is base pairing with itself across cell symmetry. The most likely way in which adenines base pairs with itself is if one is in the syn conformation and the other is in anti, i.e. a Hoogsteen base pair. However, that would break the symmetry as they are the same adenine and thus can't have two conformations. As such, I think it's appropriate to have two molecules, rather than one, in the asymmetric unit. I can make the new model easily enough by generating a symmetry mate and assigning different chain IDs but how do I appropriately calculate the new cell dimensions? Thanks, Bradley