19 December 1952

Prof. A. R. Todd

University of Cambridge

Cambridge

England

Dear Alex:

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

Prof. Todd -2- 12/19/52

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

Cordially yours,

Linus Pauling:W

19 December 1952

Mr. Henry Allen Moe

John Simon Guggenheim Memorial Foundation

551 Fifth Avenue

New York 17, N.Y.

Dear Henry:

Thanks for sending me the clipping from the New York Times on the synthesis of some coenzymes by Todd.

Todd's work is of the greatest importance. I think that his earlier work on the synthesis of nucleosides and nucleotides is probably to be considered as more important than just the synthesis of these coenzymes. This recent synthesis is a continuation of the earlier work - an application of now synthetic methods that Todd discovered.

You no doubt remember that we had Todd over here, in the spring of 1938, and that we offered him a professorship. He would have accepted it, I think, except that the British got busy and arranged for a professorship at Manchester to be given to him. I believe that Todd is to be considered the leading organic chemist in Great Britain now, except for Sir Robert Robinson.

I talked with Todd about his work a good bit this summer; we stayed with the Todds in Cambridge. In particular, I discussed the significance of his results with respect to the structure of nucleic acids. Principally as a result of this meeting with him, I have now discovered, I believe, the structure of the nucleic acids themselves. Biologists probably consider that the problem of the structure of nucleic acid is fully as important as the structure of proteins. I think that Dr. Corey and I will probably send in a note on the discovery of the structure of nucleic acids next month; we want to check up on our present structure a bit more before announcing it.

Sincerely yours,

Linus Pauling: W