Although, I certainly didn't believe it. Truly in nature, it can be described as nonpareil.
With all the years that I've heard (or taught) that all DNA is antiparallel, it was hard to believe my own eyes when I saw this structure.
Yet here is, on the screen, parallel DNA.
The image that I posted a couple of days ago came from this same structure. In that image, I hid the rest of the bases, to make it easier to see why this structure is so strange.
Here are some images that show the landmarks a bit better. I hid the hydrogens and used different rendering styles to portray the backbone and the bases.
Part of the mystery is what the people who deposited this structure were trying to do in the first place and why they made this structure. Unfortunately, it seems to published in one of those journals that isn't indexed by either PubMed or Google and there isn't a PubMed Central reference.
I'm left to wonder.
But if you want to find out, the reference is below;
Venkitakrishnan,R.P. et. al. 2004. A Parallel Stranded Dna Duplex With An A-G Mismatch Base-Pair:
(Ccataatttacc:cctatgaaatcc). Recent Trends In Biophys.Res., 1