March 20, 1953
Dear Dr. Pauling
I enclose a copy of the helical paper. You will note that I now include the αII ribbon among the possible structures. I found the version in the paper in a very
curious way: I set out to prove analytically that it couldn't be built, and as I
rotated the two residues the hydrogen bond gradually became "satisfactory!" I hope
we have time to discuss this when you are here next month, unless you wish to send
it off to the PNAS straight away.
Watson and Crick have constructed a very ingenious nucleic acid structure which they
have written (but not sent) a letter to Nature about. They will send you a copy at
the beginning of next week, as Bragg is now ill with flu, and they feel he should
see it before they send it anywhere. I have become (actively) interested in this
problem myself, although I find I lack the necessary background, a situation which
I am now remedying.
Have you heard any more about the grant for the nucleic acid program that you mentioned
in your letter to me on December 23, as I should certainly appreciate the "definite
offer" you wrote of, as I do not have any other firm prospects at the moment.
The EDSAC is at present being overhauled. When that job is finished I hope to be
able to run off the three Pattersons on sheep Hb, as the experimental part is finished.
I do not think this will be done until the end of next month, though.
P. S. The reason that the CS2S6 structure in the February Acta still shows the alternating S-S distances is that
the parameters differ from those in the MIT report you had. They differ in such a
way as to preserve the alternation when the correct conversion from triclinic to orthogonal
coordinates is made.