Original Repository: Oregon State University. Library. Ava Helen and Linus Pauling Papers
Reproduced with permission of the Ava Helen and Linus Pauling Papers. Oregon State University Library.
Medical Subject Headings (MeSH):
The Search for the Molecular Helix
Two Nobel Prizes
March 15, 1951
I am writing to thank you and your colleagues for having invited me to be Visiting Professor at Harvard next year. Under normal
circumstances I would not hesitate at all about accepting it--or, at any rate, doing everything possible to arrange here for
a leave of absence to permit me to accept it. As I said to you over the phone, the present situation is an unusual one. I
hope that you will allow me to think it over for a while, and to make a definite decision a little later--if you need to
have a definite answer soon, please let me know.
I am sure that you will not want to wait too long, and I do not want to handicap you in finding a good man for the job, in
case that I am not able to accept.
As to the matter that I mentioned over the phone, it still seems to me that it would be wise for me to stay in Pasadena during
the coming year, and to push our protein work forward as rapidly as possible. I am having a hard time to keep my feet on the
ground now--I have been working night and day, neglecting almost everything else. Corey and I have a paper coming out in the
April issue of the Proceedings of the National Academy of Sciences, in which we describe, rather precisely, two configurations
for polypeptide chains. We are hoping to have about six papers in the May issue of the Proceedings. In these papers we describe
two other configurations, and discuss the presence of these structures in various special proteins, and the experimental evidence
that the structures are right and are present in the proteins. I think that we know quite precisely the atomic structure of
extended muscle and contracted muscle, of stretched hair and normal hair (we are rather uncertain as to whether we know what
supercontracted hair and muscle are, or not). I think that I feel most excited, however, about the structure of collagen and
gelatin, and related fibrous proteins of this class. The molecule in these proteins is a triple helix, involving three polypeptide
chains that are coiled together in a helical form--resembling three springs that have been made to occupy the same cylindrical
surface. This seems to me to be an astounding structure. One nice thing about it is that we have been able to predict its
atomic coordinates very closely, and that these coordinates are supported by experimental evidence--the intensities of x-ray
reflection. Another very interesting structure is that of the keratin of feather rachis. This consists of sequences of three
layers, a pleated-sheet layer of nearly extended polypeptide chains, a layer of our 3.7-residue helix molecules, and another
layer of these molecules, staggered with respect to the first. I think that it will turn out that still more complex structures
than this exist in nature--and that it will be possible to discover them and to show just what the atomic arrangement is.