bB3dim3l Resea~?ch Council Unit
   Cavendish Laboratory,
     Free School Lane,
        Cmnbri dge,

12th October, 1gs5,

Dr. o'Sctrl?y Donahue,
University of Southern California,
Deparrtment of Chemi s t ry ,
3515 Uniwers?lty Avenue,
Los Angeles 7, Calffornfa.

Dca.r Jerry,

     1% sarry not to have written before, but wo have only
$mt got round to polgglycinc II qpfn. X enclose the results
of our old calculat%ons.  They rxr~: essentially the same as yours
(you accidentally omitted the spacing 2&O in your letter). On
the same aheet X: have put the very rou&:h mexxarements that Alex
and X made from the IJature picture, together with those ~?EKI~ by
Gllfott from the orfginal.  Unfortunately he only sent us these
after the paper had been pabUshed. You wfll see that our
~aau3Pements, whfeh are presui'~~bly inaccurate, a~grce well with
o;,r calculations, if the reflections are ascumod to be dfLPf`use,
whereas your measurements agree very well with Ellfott's, Very
tiP6somer  \Ye iare now doing further calculations and T will let
you know when we arrSve at z30m~ conclusion.

      Gunther was here last week and 1 prom2sed that 1 would
wrr%to to you about your *joint paper.  Our criticisms are much as
bcfox~ except that WQ can now make them proclss,

1. ?/e do not like the tautommic shift in guanine.  You
   nowhere point out that ff guanine does undergo a
   tautomerfc shift it can $.~st as well pair with
   adenine 8s with an&her WanMe.

2, It is not true that there are two different possible
   structuras baGed on your pairing.  In theory ,there
   are three*  They c8n be syruibolised as

.


2

The last two Etre not the same. It ia just this @art of
armMbp.dty uMd3. rmkes us question the acceptability of your
model huildin~~.  Have you, or have you not got acceptable
~~~~imates fop one of these structures; c;lnd if sop which ik3
it3

     Findly f shouLd pofnt out that while wa bslieve that
poly A form8 something like the type of sb?ueture you doscribs,,
*here ia good evidenoe that poly U ia amoq>hous.       .

      All the family are well, tiisax?pt that G3&rielle broks
hop arm recently, but it is mending weZ1. There is %t Fa~x~3ay
+53xiety Nucleic3 acid conferoncs in Loru3on at the ad of this
rnee~ # am3 we we expecting Paul 3)aty to visit UES after thze con-
ference *

31th boat wishsa to both you and Pat.

.


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