19 December 1952
Prof. A. R. Todd
University of Cambridge
I was pleased to learn from the New York Times that you and your group have synthesized
three coenzymes. I think that this is fine.
Dr. Corey and I are much disturbed that there has been no precise structure determination
reported as yet for any nucleotide. We have decided that it is necessary that some
of these structure determinations be made in our laboratory. I know that the Cavendish
people are working in this field, but it is such a big field that it cannot be expected
that they will do the whole job. On the other hand, we do not want to duplicate
their investigations - it is more important that another nucleotide determination
be made, in case that they carry out one of them. Probably I shall write to Bragg
or Cochran pretty soon and ask which ones they are working on. If there is no objection
on their part, we should like to ask you to provide us with material, if you have
some crystalline preparations of nucleotides or related substances that you feel would
be especially worth while investigating.
I may say that we probably shall try to determine the structure of some phosphate
diester, perhaps not of the nucleotide class - information about the structure of
phosphate diesters can be carried over directly to nucleic acid.
We feel strongly the necessity of having precise information about these substances
because we have, we believe, discovered the structure of the nucleic acids. I think
that it will be about a month before we send off a manuscript describing the structure,
but I have practically no doubt about the correctness of the structure that we have
discovered. I feel very grateful to you for having given me reliable information
about nucleic acid, this summer. Our structure corresponds to the specifications
that you laid down; in particular it involves 3', 5' linkages between the P-ribofuranose
rings, by way of phosphate groups.
The structure is really a beautiful one. It is hard to describe without some drawings,
which have not yet been made. I shall keep you informed.
I enclose a copy of a letter to Bragg, asking him for information that would keep
us from duplicating work that is being done in his
laboratory. I may say that we have been especially interested in leaking a structure
determination of ATP. We have surmised that some unidentified crystals for which
we have some x-ray data might in fact be ATP, but this has not yet been verified.
If you have any preparation of a nucleotide that is in the form of crystals, even
microcrystals, and could give us a small amount - enough to recrystallize into larger
crystals - we should be happy to begin the investigation of it, provided that it does
not interfere with your collaboration with the Cavendish group.
With best wishes to you all for Christmas and the New
Year, I am