Letter from Rosalind Franklin to H. Fraenkel-Conrat
During her 1954 visit to the United States, Franklin met or renewed acquaintance with many virus researchers, who were able
to send samples of their virus material and brainstorm with her on her x-ray diffraction findings. Heinz Fraenkel-Conrat at
the UC Berkeley Virus Laboratory was especially helpful, sending a variety of heavy-atom substituted TMV preparations. In
this letter, Franklin requested some unsubstituted TMV protein to compare with the mercury-substituted samples he sent previously,
and also asked if it would be possible to work with him for a few weeks during her upcoming summer visit.
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2 (127,144 Bytes)
1956-04-20 (April 20, 1956)
University of California, Berkeley
Original Repository: Churchill Archives Centre. The Papers of Rosalind Franklin
Reproduced from the Franklin Collection at the Churchill Archives Centre with the permission of the copyright holder.
Very many thanks for the latest Hg-protein. It does not seem to have such a strong tendency to disaggregate as the previous
preparation, and I am quite hopeful of obtaining a well-orientated specimen from it, though this will probably take some time.
I find that washing the glass capillary repeatedly with a little Hg-protein solution progressively reduces its tendency to
cause disaggregation. Washing it with buffer does not have the same effect.
Now may I make one more small request before making a big one? Could you spare me a few milligrams of your unsubstituted TMV
protein, so that I can compare your Hg-protein directly with your protein rather than with Schramm's?
The big request concerns the visit to the U.S.A. which I am hoping to make this summer. I hope to be able to come over for
two months, starting with the Gordon Conference in June. I should, of course, like to visit Berkeley, and I wondered whether
it would be possible for me to spend a few weeks (up to one month) in your laboratory in order to learn from you something
of the techniques of handling virus material. If I did this, one possible way of spending my time might be in attempting to
prepare, under your supervision, some new heavy-atom derivative of TMV, such as would be useful in the X-ray work (we particularly
need a heavy atom bound to a specific site on the outside of the particle). However, any alternative suggestion from you would
Perhaps I should mention that I was originally trained as a chemist, not a physicist!
If you think that such a scheme would be possible, what dates would be most convenient for you? I know that you will be in
the East for meetings in June, but do not know how soon you will be returning to Berkeley afterwards.
There is nothing new here since I last wrote to you except that we now have the radial density distribution for both CV4 and
U2 strain of TMV. Both have, like normal TMV, the RNA peak at 40 A radius. The protein density peaks are in the same positions
as for TMV but of varying relative intensities.