A. Rich Linus Pauling 9 December 1952
Preparation of fibers of nucleic acid
I suggest that you try to make well oriented fibers of sodium thymonucleate or other
nucleic acid preparations by the use of plasticizers.
The fact that 50 percent relative humidity seems to be required to give good fibers
suggests that substances containing hydroxyl groups would be satisfactory plasticizers.
I think that you should try adding a little glycerine to the solution. Perhaps ethylene
glycol or diethylene glycol would be worth trying. In fact, perhaps all of these substances
should be added to the same preparation - mixed plasticizers often are more effective
than the individual plasticizers.
As to other substances, urea and salicylic acid and guanidinium ion might all be worth
trying.
There is a possibility that dibutyl phthalate would be
useful.
For one preparation you night try putting all of these things in the solution, with
the nucleic acid, the plasticizers being added in rather small amounts.
I am also asking Dr. Marsh to make a spectrometer investigation, and to calculate
a radial distribution function. Would you turn over to him about 0.5 g of a preparation,
for this purpose. If your powder photograph of the sodium thymonucleate taken directly
from the bottle gives as good a powder photograph as the recrystallized material,
I suggest that you give him a sample of the material from the bottle. Small amounts
of impurities would not be important.
Dictated by Linus Pauling
Signed in his absence:W
cc: Professor Corey L.P.
