Subject: DNA Base Pairing: Watson-Crick/Hoogsteen/"Curtis"

From: "Rzepa, Henry" <[email-masked]>
Date: Tue, 19 May 1998 18:29:49 +0100

A recent "popular" article in the New Scientist magazine (May 16) suggests that
Watson-Crick might have been wrong, and that the  DNS bases pair
up differently. The suggestion comes from an artist called Curtis, who
built geometric
models to come up with the theory, and apparently got Maurice
Wilkins interested.

The article interestingly fails to mention energetics at all, and
does not note the curious similarity of the Curtis proposal to
Hoogsteen's pairing for AT.  Curtis proposes a similar pairing
for CG (which  Hoogsteen never did).  Apart from the fact
that the  geometries Curtis assumed for his model are quantitatively
wrong, does/has anyone had the energy/inclination to try to build
the double helix proposed using "Curtis pairing", but using the
"accepted" geometries for his version of the pairing?

On this point, are there any unequivocal pdb structures showing
Hoogsteen pairing? I thought I found some, but they do not show
it.

I wrote a "letter to the  New Scientist editor" in the form of the following
web page

http://www.ch.ic.ac.uk/newscientist/curtis/

I await the outcome. However, in the past,  I have found these
popular science magazines tend not to want to confuse their
readers with difficult arguments (such as the difference between
C-H...O and  N-H...O bonding, leaving aside the fluoro-toluene
results reported by  Kool and commented upon by  Seddon).

Dr Henry Rzepa,  Dept. Chemistry,  Imperial College,  LONDON SW7 2AY;
mailto:[email-masked]; Tel  (44) 171 594 5774; Fax: (44) 171 594 5804.
URL: http://www.ch.ic.ac.uk/rzepa/