2 January I970
Dear Dr. Traub
I was glad to receive the reprints you sent me.  In recent years I have rather lost touch with the subject of collagen, so I was especially pleased to see that your work leads to a model which is fairly close to the old collagen II model.  We realized in 1961 that not much further progress could be made on the structure of collagen unless repeating synthetic polypeptides were studied.  Personally, I never believed Ramachandran's model with the two hydrogen bonds.  Apart from anything else, it seemed to me to be stereochemically unlikely.  Both Alex Rich and I decided, however, that we did not wish to get involved further with the problem, mainly because of the competing interest of protein synthesis and the genetic code, although we did feel a little guilty about not following up our earlier work.  You will realize, therefore, that I am especially delighted that you should have done such an excellent job and particularly as the result has come out, in the way we hoped.
With all good wishes for 1970.
Yours sincerely
F.H.C. Crick