July 2, 1977

Dr. A. Klug, If._X.S,
MRC Medical R%5%4w& cuuxtcil
Laboratory of Molacular Uology
Uuivcrrrity Poatgraduatart Madioal School
Hills Road, Cambridge, C32 2QH
Eugland

Dear Aaron:

  Thad you fox put letter of 23 June amd th% Int%ml-
"Ram uf ttieting uf DNA".  Rather than reply at length could you
ask Miohael Levitt to show you the letter f have juetwritten ta
bite concerning the paper by Cam&i-0tm-o md F'eleenfeld. You
will se@ that the vhola qu%etlon of the conformation of suparh~lical
DNA ia 8olutiun ir full of difficultias. ?'ur aample, are you
sure that such DNA is nut toroidd at wry mmll /bLfO

   I don't think the varbtbm of the tmUaentation coastant Path
\ALI %s of ma& uaa by itself.  It'@ clam we &all wed, in addit%on,
the nthemd dietribatioa" of  IAL B both bllcotrnd a amm off&f "c)
and also around great%r valuers of I ALI.  We shall also need the
drtailar of the X-ray rcatt%riug ti solution. Oa the theoreticerl
eide a lot nerads to b% cl%ared up. 8cqmfu.U.y a theury till
6m%ntually emerge which fits the %xp~xSmattal date Za a rmturcrl my,

  I suggest m leave further dircuesion dill w% m%t in lkrmark.
Rav% you s%%n th% preprint by &ummn and Trifonov? I am
emding a cupy to Eischael just In cm% ha ioaaen't havs on%*

   I mmlose a sU@.ttly xeaoltaed version of the shozt notm for the
CSH Sympo~fwt.  As putt will mm, it eover~ a ttuabx of p6bts which
w% have breen cormspondtig about.  I f%%l that ie m&e or twD places
it fe soux&r than th68 account fn ycmr paper.

continuad . . m . +


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