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Defining the Genetic Coding Problem, 1954-1957
Letter from Francis Crick to Jerry Donohue (April 28, 1956)
As you may see from the enclosed (one is for Max) I finally got around to finishing and writing up the base pairings I started
3 years ago, mainly because it enabled me to get an expense-paid trip to Washington. I must explain footnote 9, a point you
may remember we had not a little discussion over, with the opposite conclusion. Pauling, who as a member of the National Academy,
had to approve and submit the manuscript, said he had wondered about the triple hydrogen bond ever since Jim's and your
structure appeared, and then he decided to take this opportunity to make this point in print. I thought it was pointless
to explain that we had gone over this before, so there it is.
Jack Dunitz told me he had heard (from Dorothy?) that you and Alex had worked out an RNA structure, but no details were available.
Is this true? I haven't been up to Cal Tech much lately (it's so near and yet so far) since we finished that polyglycine
thing, so I don't know what they up there might know. These seem to be cryptic days. First the RNA rumors. Then you and
Alex publish a collagen structure but don't let on what it is. Then Bear announces he has tested your structure, but
doesn't state how it came out. Then Max writes he has an alternative to Harker's method, but that's all he says.
O tempora, O mores! I have been tied up with other structures - all non-biological - and have been going over to
UCLA often to use the SWAC with Ken Trueblood (who, by the way, will be at
Oxford next fall). He periodically receives a bundle from Oxford, and then is up to his ears in B-12 for several sessions,
but it appears the main job is done at last.
PS Max wrote that he would ask the editor of Nature if you and Alex could answer our note. This may be all right, but personally
I don't see what there is to answer.
A Note on the Structure of Polyglycine II
Very recently Crick and Rich suggested a structure for the new form of polyglycine, "polyglycine II", first discussed
by Bamford, Brown, Cant, Elliott, Hanby, and Malcolm. The test of the correctness of a proposed structure lies not only in
whether it is a reasonable one, but, a fortiori, in whether it is in agreement with experimental results. In the case of polyglycine
II the principal experimental results are the X-ray diffraction data obtained from powder samples by Bamford et al. Crick
and Rich stated in their paper that they had made a comparison of the observed intensities and spacings of the diffraction
lines with those calculated for their structure. Instead of presenting this comparison they stated that "Their X-ray data
(Bamford et al.) are in good qualitative agreement with our calculations".
We have now also made the calculations of spacings and intensities and have compared them with the photograph published in
Nature. Our results will be published elsewhere.
University of Southern California, Los Angeles
Richard E. March
Robert B. Corey
California Institute of Technology
Crick, F. H. C., and Rich, A., Nature, 176, 780 (1955)
Bamford, C. H., Brown, L., Cant, E. M., Elliott, A., Hanby, W. E., and Malcolm, E. R., Nature, 176, 396 (1955).