CALIFORNIA INSTITUTE OF TECHNOLOGY

PASADENA, CALIFORNIA

DIVISION OF BIOLOGY

October 6, 1960

Dr. Arthur Kornberg
Department of Biochemistry
Stanford University Medical School
Palo Alto, California

Dear Arthur:

The samples and your letter arrived today and we will carry out the biological
assay experiments this week-end.

I will let you know what we find out.

I enclose a copy of the petition concerning Pauling that was circulated among
the faculty here. About 100 signatures were obtained. It was sent to Senator
James 0. Eastland, Chairman of the Internal Security Subcommittee of the
Senate Judiciary Committee.

Concerning molecular models, the situation is complex. As you know, molds
for atoms were made here and a fair nmber of atoms
made of a slightly flexible plastic material.
pyrimidine and purine rings can be readily formed.
apiece to make so a turn of a DNA helix would cost $lOOO-$l5OO.
these were intended for small peptides,  etc. and are not well suited for
large structures, proteins or nucleic acids because of excessive weight.
One has to build a supporting framework.
exists although if you would like to come down for a few days we could probably
round up enough atoms to make such a model.

This is flexible enough that
  The atoms cost about $1

Actually

No DNA model made of such atoms now

Alan Hodge who recently came here has been experimenting with the use of these
molds to make atoms out of polystyrene foam.
glued together in cases where rotation is not desired and seem to offer
numerous advantages.  There are still a few problems to be worked out in
connection with couplings and thus far Hodge has just been making small batches
by hand.  I think it is possible that in a couple of months this will be  far
enough along to provide an excellent solution.

These are much lighter,  can be

Meselson has a DNA model made of metal plates and spokes.
filling, but he
glucose positions with this.
and try with it.

It is not space-

thinks we could get some pretty good ideas about the possible

It would be available if you would like to come

The La Pine models are derived from the same atomic scale as the Caltech atoms,
with a little greater magnification.
is that rings cause some difficulty.

They are not flexible and qy understanding

Dr. Arthur Kornberg -2- October 6, 1960

I have wanted a DNA model also, but at this point I think I will wait to see
how Hodge's polystyrene foam atoms develop.
solution.

I really think this will be a

Presumably whole purine and pyrimidine rings  could be cast at once.

If you or any of your group would like to come and use the models or atoms
available here we would be very glad to have you.

With best regards ,

R. L. Sinsheimer
Professor of Biophysics

RE sc


Enclosure