Sunday, July 15, 2007

A Strange Molecule

Last Wednesday an image of strange base pair was published on Discovering Biology in a Digital World [Puzzle]. We were asked to figure out what was so strange about his base pair (see below). I got part of the answer but not the complete answer.

The answer has already been posted but I won't link to it just yet in order to give you a chance to figure it out. Please don't comment if you've already seen the answer.

Here's another view that promises to be a lot more helpful.


  1. Whoa, that bottom one does give it away- wouldn't the strands containing that base pair have to be oriented parallel rather than antiparallel? That's bizarre. Is there actually a known duplex structure in which that's true? (I think there are RNA parallel triplex structures known, but I'm not aware of any kind of parallel duplex let alone a DNA one.)

  2. Cool, eh? Yes, it's double-stranded DNA with parallel strands [It's Still a DNA Puzzle, but this is the Answer]. You can see for yourself by fetching 1r2l from the PDB or Nucleic Acid databases.

  3. That is genuinely strange- thanks for the neat post.