U N I V E R S I TY

WASHINGTON

THE HENRY SHAW SCHOOL
     OF BOTANY

SAINT LOUIS

November 28, 1954

Dr. Rosalind Franklin
Birkbeck College Crystallography Laboratory
21 Torrington Square
London, W.C.l., England

Dear Dr. Franklin:

I was very glad to get your letter and to learn that you

are ready to look at some of our proteins.
our collection of nonvirus proteins to determine sedimentation
constants at the moment and within a week or so I shall be able
to set aside some B8 for you.  I will write you air mail at the
time the material is shipped so that you can be ready for it.

  Your information on the high density shell in TMV is of
great interest to US.
said that since his ca culations show that the zone has a thick-

fact represent the location of virus PNA.
concerning the location of PMA will be very important to us for
it will serve as a useful guidepost in our thinking about the
relation between "MY and the nonvirus proteins.
your observations on this problem.

We are going through

I heard from Caspar the other day and he

ness of the order of 5 B , it is possible that the shell does in

Any conclusive evidence

I would welcome

In the last few weeks we have been studying the distribution

of TEfv in specific gravity gradient tubes in the ultracentrifuge
in the hope of finding in our bulk virus fractions which differ
in nucleic acid content.
which is homogeneous in the PseIJius apparatus can be separated
into at least two and possibly more fractions with respect to
specific gravity.
a high density shell in W.  If we can prepare virus fractions
which differ in specific gravity,  I should very much like to
send you some for examination.

Thus far, it does appear that TMV

Again this problem may bear on your finding8.f.

   In any event, I am delighted to know that you are ready to
look at our material and shall do all I can to keep you well
supplied with samples.

Sincerely yours,

A

Barry cbmmoner

BC: bl