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. Albert Siegel at UCLA was
working with TMV, and in this letter Franklin told him of her latest results with his U1 strain of TMV.
Number of Image Pages:
1 (68,329 Bytes)
1955-04-27 (April 27, 1955)
University of California, Los Angeles. College of Agriculture
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.
I have at last got some good photographs of an orientated gel prepared from your U1 strain of TMV. It closely resembles the
photographs of the strain I had earlier from Pirie. This is a satisfactory result, as it means that the difference observed
for U2 was certainly due to the difference in strain and not to the difference in method of preparation. The U1 is, however,
much more difficult to orientate than Pirie's preparation, and I have not yet succeeded in getting a good dry specimen
of it. A much higher concentration is required, in U1 to produce a spontaneously birefringent solution. Would you expect
this difference to be due to the presence of the brown substance?
I intend to write a short note on the differences in the X-ray diagrams obtained from the 3 strains of TMV and from Knight's
cucumber virus, CV4. I will send you a copy when it is written.
I should be extremely grateful if you could spare a fresh supply of U2 for me some time. In some ways it shows a greater
regularity of structure than the other strains, and I should like to do some further work on it.