DNA With Parallel Strands

 


A week ago I asked if any of you could identify a strange molecule that looked like a base pair [A Strange Molecule]. Steve LaBonne recognized that the bases were flipped and the strands were parallel.

Here's an image of the complete structure from the PDB Database [1R2L]. Unlike normal double-stranded DNA, in this structure the strands run in the same direction from top to bottom. The 5′ ends of each strand are at the bottom.

This is very unusual. So far, it's the first example of such a molecule. Nobody thinks that a parallel-stranded DNA can exist inside a cell but who knows?

Sandra Porter at Discovering Biology in a Digital World found it [It's still a DNA puzzle, but this is the answer]. Thanks Sandra.