8th June 1953.
Professor Linus Pauling,
Gates and Crellin Laboratories of Chemistry,
California Institute of Technology,
I am indeed grateful to you for your willingness to help me in the two applications
I have recently made and hope that it will not be long before I know something definite
about them. Having talked about U.S.C. to a number of people I think that it was
fortunate that I was not tempted in that direction.
We are working very hard to get all our conclusions about proteins, nucleoproteins
etc. into final form and it's quite a lengthy job. As regards calf thymus nucleoprotein,
we do not think that the histone is present as an α-helix and that the nucleoprotein
complex is essentially histone nucleate. We have similar but perhaps less definite
evidence regarding herring sperm nucleoprotein. Such evidence as we have on the nucleic
acids seems to indicate that differences can exist but we really have done very little
yet except obtain some fairly good scattering curves.
I am interested to learn that you are re-attacking the collagen problem. As we said
in our contribution to the Royal Society discussion (now published), our evidence
points towards a structure of the ɤ-type. In the last month or so I have taken up
this matter again and feel more than ever convinced that this may be part, at least,
of the answer.
We have not quite finished our work along these lines but my general idea is that
of a two phase system, one phase being ɣ-helix (with every third Cβ omitted) corresponding
to the proportion of glycine present, and the other phase containingtjttproline and
hydroxy proline. Such a claim might fit in with some of the low angle diffraction
and electron microscopical evidence as well as with our own data. According to your
Royal Society contribution, you seem to be opposed to the possible existence of the
J-helix on grounds of stability but I am not altogether certain that this is an over-riding
objection. In any event all we can do is to compare theory with experiment and see
what comes out of it. We are at present engaged on a detailed comparison of the type
we used for the #-helix and the globular proteins and I will let you know the result.
I shall be at the Stockholm Congress in July and hope very much to see you there when
we can talk about this and other matters.
My warmest good wishes to you and Mrs. Pauling.