Letter from Donald L. D. Caspar to Rosalind Franklin
Biophysicist Donald Caspar's recent doctoral research on TMV, using heavy-atom substitution, was of great interest to
Franklin. They corresponded frequently and he spent part of the 1955-56 academic year in England working in Franklin's
lab. In this letter he commented on a manuscript that Franklin had sent to him and to James Watson for review.
Item is handwritten.
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Caspar, Donald L. D.
University of Cambridge. Cavendish Laboratory
Original Repository: Churchill Archives Centre. The Papers of Rosalind Franklin
Reproduced with permission of Donald L. D. Caspar.
Enclosed is the drawing for my paper and a retyped copy.
Jim had some suggestions regarding your paper -- I don't know whether you will want to take the time to make changes but
I thought I'd send them along anyway. He feels he doesn't deserve credit for the idea that the RNA is axially located,
and that your description of the EM work is confusing. It might be better to say that when the protein is partially removed
from the virus by gentel [sic] means the RNA can be seen as an axial core in the EM, but that since this may be a collapsed
structure it does not necessarily represent the location of the RNA in the intact virus.
Since the A-protein Fourier is the most important part of the paper it might
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pay to cut out some of the other details to help emphasize it. You might leave out the list of preparations -- Though mentioning
that you used Frankel-Courat's normal stain and Schramms A-protein, and that the comparison of the two is justified by
the uniformity of normal strains. The two paragraphs from the bottom of page two to the top of page three could be left out.
After the description of the radial Fourier (middle of page 4) you could insert a short paragraph pointing out that the changes
in the non-equatorial reflections between TMV and the repolymerized A-protein using newly determined helical parameters also
indicates that the structural difference occurs at a radius of about 40 angstroms.
Nature is unlikely to accept the abreviations [sic] -- particularly RAP which is a rather unpleasant name. The litterature
[sic] is getting really too full of abreviations [sic] so if you can think of any other euphemism, it would almost certainly