29 March 1953
Dr. Max F. Perutz
Dear Dr. Perutz:
I am writing to try and clear up a situation that may have caused you some concern.
Word has reached me that you felt that I had obtained the idea of coiling helixes,
in α keratin, from Crick, and had not acknowledged my indebtedness to him.
I do not believe that you were in Cambridge when I visited there last summer. I had
a long session with Crick, Kendrew, and Huxley. There was only brief discussion of
α keratin at this time, and, if my memory is correct, only a few sentences were said
about the coiled coil, as Crick calls it.
We discussed the fact that the 5.14-A meridional reflection offered some difficulties
of explanation, and that also there seemed to be a discrepancy in the density of α
keratin. The discussion was very brief. Then Mr. Crick asked me if I had ever thought
of the possibility that the α helixes were twisted about one another. I answered
that I had. So far as I can remember, nothing more was said on this point.
I did not say anything more on the point because, although I knew that the simple
idea of a coiled coil could account, at least roughly, for the presence of the 5.15-A
meridional reflection, I did not understand as yet how it accounted for the density,
and I was not sure that the explanation of the meridional reflection was completely
satisfactory. I assume that Crick said no more about the matter for essentially the
same reason. Astbury and MacArthur later asked me if I knew how to account for these
troublesome features, and I said that I thought that I did, but was not yet sure.
I felt reasonably sure only after having completed some calculations of intensities,
and having formulated the fundamental idea about the automatic conversion of a straight
helix into a compound helix through a repeating sequence of amino acid residues.
To summarize: I think that the only information about the coiled coil that I obtained
from Crick was contained in his question of me, when he asked if I had ever considered
twisting the α helixes in α keratin. The idea was not a new one to me then, but it
had not yet been well worked out, and it seems to me that the way in which we worked
it out, as described in our paper in NATURE, is much different from that discussed
by Crick. I hope that if my memory about the discussion in Cambridge is at fault
Mr. Crick will let me know.
If you have any further comments to make on this matter, I should be glad to learn
I am hoping to see you when I make a brief visit in Cambridge in a few days.
cc: Dr. Crick