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Letter from Linus Pauling to Alexander Rich. December 9, 1952.
Pauling writes to suggest that Rich try to make fibers of sodium thymonucleate by the use of plasticizers. Once done, Pauling requests that Rich send a sample to Dr. Marsh, who is making a spectrometer investigation of the substance.


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.

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