DNA in ASCII

They might as well call it a picture of a rope, or the twisted pair of an ethernet cable, or something equally fanciful.

The picture is horribly wrong because:

- It's left-handed and 10bp/turn. Only Z-DNA is left-handed, so it's obvious (to anyone that's taken a course in biochemistry) that they're missing two base-pair "rungs".

- If it's not supposed to be Z-DNA, where are the major/minor grooves?

In fact, none of the known unstrained DNA geometries match the picture: A-form DNA has 11bp/turn, B-form DNA has 10.5bp/turn, and Z-form DNA is 12bp/turn.

"Artists" get this wrong frequently, but without any good reason because these structures have been well-known for several decades. Furthermore, incorrect pictures undermine biochemistry's beautiful basis: structure determines function. Would it have troubled them that much to search for correct information on the Internet (or a book)?

See https://secure.wikimedia.org/wikipedia/en/wiki/File:A-DNA,_B... and http://en.wikipedia.org/wiki/Z-DNA