F. C. Bawden (1908-1971) was a pioneering plant pathologist and virologist based at the Rothamsted Experimental Station in
England. He and N. W. Pirie were longtime collaborators in plant virology. During 1957 Franklin's team studied a number
of different virus samples provided by Bawden, and elucidated their structures.
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1957-10-18 (October 18, 1957)
Bawden, F. C.
Rothamsted Experimental Station
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.
The measurement of the radial density distribution in the cow-pea and tobacco farm of the TMV strain which you sent me a long
time ago are at last completed. As you will see from the enclosed graphs the cow-pea form is very different. Its X-ray diagram
is also strikingly different from that of normal TMV. The difference between the tobacco form and normal TMV is slight, but,
since there is a noticeable difference on the photographs, it is probably genuine.
The most variable part of the structure seems to be the part of the protein which lies inside the nucleic acid. This is true
also of the other strains which we have examined.
Very roughly, the difference between normal TMV and the cow-pea form is of the same magnitude (but not of the same kind) as
that between TMV and CV4.
The density in the cow-pea strain falls off very sharply beyond 80 A, suggesting that it has less of a groove -- or smaller
protruberances -- than the other strains.
Is anything published or known about chemical differences?
We are proposing to publish the density distributions of the various strains in a short paper in Virology. I shall send you
the manuscript when ready, but meanwhile it would be nice to have your comments and to hear of any new information about them