22 November 1955

Dear Peter:

I haven't been able to find the letter that you sent me a few days ago, with a list of expenditures which you have made for me during the past year, but I expect to run it down shortly, and then I shall send you a check.

I enclose copies of my letters to the National Academy of Sciences and Matt. Ye

Your letters of 14 and 15 November have also reached me. I like the idea of your doing work on bacterial flagella and on viruses. The news about bushy stunt virus as having icosahedral symmetry is surely interesting. I suppose that the molecule consists of subunits, perhaps arranged in a way similar to that of the atoms in Mg88(Al2Zb)49, which we describe in our letter to Nature about three years ago, and which I also described in my talk in Stockholm in 1953 and in the American Scientist for April 1955. You probably remember that we had one atom at the center, twelve outside of it at the corners of an icosahedron, twenty outside of the icosahedron, at the corners of a pentagonal dodecahedron, then twelve out from the twenty pentagonal faces, giving a rhombic triacontahedron, end so on. If the fundamental units of bushy stunt virus are approximately spherical, then one of these complexes would be expected. Perhaps, however, the fundamental units are not spherical, but are elongated, possibly even pointed, and the big molecule consists of units of only one kind crystallographically. My memory is that bushy stunt virus has molecular weight about 8 million, and one usually expects protein molecules (single polypeptide chains) to have molecular weight perhaps 20,000. Of course, I suppose that the inside of the molecule is nucleic acid, and the protein exists only on the surface. The point group 532 has, I think, 60 equivalent positions, so perhaps the protein part of the molecule consists of 60 small protein molecules that fit together to constitute the outside layer of the nearly spherical virus.

I remember Weibull. I think that it would be fine for you to work with him, and perhaps also with Sjostrand. It is a little hard to see how to get Theorell into this, but you might be able to make the preparations in Stockholm and x-ray photographs back in Cambridge under a new fellowship.

Do you know how good the x-ray photographs are that Astbury got of bacterial flagella? I don't think that I ever saw the original photographs, but I have seen a diagram that he prepared of them, and I think that it has been published, a year or two ago. There is quite a bit of detail on the x-ray diagram. I feel sure that additional x-ray work, perhaps concentrating on the directions in which the 1.5 A reflection and the 5.1 A reflection are observed to occur, relative to the fiber axis, and correlation with the 3-strand structure as shown by electron microscopy, might permit one to reach definite conclusions about the way in which the alpha helixes are twisted about one another. Of course, there is a reasonable chance that the flagella are to be described in terms of globular proteins, which clamp onto one another to produce the strands.

I saw Delbruck on the street a couple of days ago, and he told me about the letter to Alex and Francis.

I have been so busy with various things that I haven't been able to settle down to work on collagen. I think that I told you that we would probably describe our structure for collagen, or at any rate, our thoroughgoing studies of structures with a repeating unit of three residues forming two hydrogen bonds. There is, of course, the difficulty that some peptides have been got from collagen hydrolysates in which proline and hydroxyproline are adjacent.

Thanks for telling me about Lord Halsbury. I had surmised that his grandfather was the man who had been knighted and then made an earl, and who was Lord High Chancellor under Queen Victoria. I wondered, however, how it came about that the present Lord Halsbury did not go to Oxford or Cambridge, and instead was trained as a certified public accountant, and then later studied chemistry at the University of London. I thought that perhaps he was not very close in the line succession, and it was not expected that he would become the earl.

Mrs. Jordan lives a block above us on the hill, to the west of Sierra Madre Villa. She is somewhat crippled by arthritis, I don't remember whether you have ever met her.

I made a trip to Washington a week ago, to testify before the Senate Subcommittee on Constitutional Rights. Everything went along very well. You may have seen something about it in the newspapers, this is called the Hennings Sub-committee.

Mama and I are going to have Thanksgiving dinner with Pauline, and probably also, in the evening, with Eddie Hughes. Also, Professor Huisgen is to come in about today. You probably remember our visit at his apartment in Munich. He is giving the chemistry seminar this week.

Love from

Linus Pauling:W

22 November 1955

Professor N. F. Mott

Cavendish Laboratory

Free School Lane

Cambridge, England

Dear Mott:

My son Peter, who is working with Kendrew, has suggested to me that you might be interested in my opinion of the work being done by the Medical Research Council Unit on the structure of biological materials, consisting of Perutz, Kendrew, Crick, Watson, and other workers in the Cavendish Laboratory. I am happy to have an excuse for writing to you about this work.

You know that my colleague Professor Robert B. Corey and I are very much interested in the problem of the structure of proteins, a problem that is being attacked by Perutz and Kendrew and their collaborators (they are also working on other problems, such as that of nucleic acid, but I shall discuss primarily the protein problem). Perutz and Kendrew have for a number of years been making a vigorous attack on the structure of crystals of globular proteins, especially hemoglobin and myoglobin. There is no doubt whatever in my mind about the value of this work. I think that the problem of determining the detailed molecular structure of globular proteins is one of the most important of the scientific problems, in any field, now under attack. There are not many people engaged in the attack on this problem, probably because it is such a difficult one, and requires such an extraordinary combination of abilities, that the prospect for significant results in a short time is small.

Aside from your Medical Research Council Unit, this problem is being attacked to some extent by Harker and his associates in Brooklyn Polytechnic Institute, by Mrs. Hodgkin (who is, however, primarily interested now in vitamin B12), by Barbar Low, by Bernal and people in his laboratory, and by some of the workers here in Pasadena. Professor Corey and I feel strongly that no other group in the world has made contributions to the problem of the structure of globular proteins that are comparable to those made by Bragg, Kendrew, and Perutz and their associates. Their work is large in quantity and high in quality. I hope very much that it will be possible for the members of this Medical Research Council Unit to continue to carry on their work without interruption, and under favorable circumstances.

I do not know what the problems are in connection with their

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continuing this work, but I am writing to tell you that Professor Corey and I feel strongly that it is important that they do so and we have no hesitancy in telling you about the high opinion that we have for the work of the Unit.

Sincerely yours,

Linus Pauling:W

P.S. I am sending a copy of this letter to Todd. LP