Kornberg ”

WASHINGTON UNIVERSITY

 

SCHOOL OF MEDICINE
SAINT LOUIS

DEPARTMENT OF MICROBIOLOGY
EUCLID AVENUE AND KINGSHIGHWAY August 19, 1957.

Dr. Joshua Lederberg
University of Wisconsin
Madison, Wisconsin

Dear Josh:

As you probably know my visit to Stanford materialized into a decision to ac-
cept their offer. Aside from the obvious climatic and geographical attractions, I
think there will be better opportunities for graduate student teaching and a degree
of intimacy between the medical and university that will minimize trade school be-
havior. ‘Troublesome administrative problems will inevitably arise, but I think the
mechanisms for solution at Stanford will be easier to reach than at so large and
complex a place as Berkeley. It's awful leaving Washington University; the tradi-
tions of scholarship are well established here and we have a number of good friends.

The whole group of us here will be moving and we will be able to appoint two
additional people who I hope will better represent physical and organic chemistry
than we do nowW. We've been able to plan the space we will occupy and should be
moving late in the spring of 1959 when completion of the buildings is anticipated.
With everybody helping, the move shouldn't cost us too much time or anguish.

I would have liked to write you sooner about the isolation of DNA but I had,
and am afraid still have very little to offer. the DNA we have used routinely in
our work is prepared from calf thymus by the Kay and Dounce procedure. We have also
used T2 phage DNA prepared by osmotic shock and centrifugal removal of the ghosts
and Hemophilus DNA prepared by Zamenhof's method using the Sevag procedure. I have
reservations about the application of detergent or Sevag procedures to getting out
E. coli DNA since we know that a DNAase which degrades T2 phage DNA withstands these

- Manipulations to a considerable extent. The use of RNAase destroys an inhibitor of
DNAase which masks a considerable amount of the DNAase activity in crude fractions;
Pardee and Kozloff have described this phenanena. The use of Mg** @inders, such as
citrate or versene, is not a certain way of inhibiting DNAase, since we know of the
existence of l; distinct DNAases in coli and the metal requirements may vary widely.
We would of course prefer to avoid the use of strong acid and alkali and heat. Up
to recently we haven't needed £, coli DNA and weren't in a position to distinguish
"good" from "bad"; as a result we haven't given this problem a lot of attention.
For a few weeks this summer, Dale Kaiser and Dave Hogness were making some passes
at coli transformation and spent most of their time trying to learn how to extract
coli DNA,

Qur own work has taken a hopeful turn, After several wearying months of trying
to free our enzyme from its contaminating DNAases we seem to have a useful prepara~
tion. First we were able to show net synthesis that more than equals the DNA we use
asprimer". The next finding was that more thymus DNA "primer" was necessary with
high levels of the purified enzyme, than with comparable levels of the less purified
preparations. However, preincubation of the DNA with one of the discarded fractions
activated it about 3-fold; similar activations are possible with extremely minute
aQ—

amounts of pancreatic DNAase, With the purified enzyme,samples of DNA eluted from
a resin column (cteola) with increasing salt behave differently as "primers", All
this becomes more and more suggestive of end groups as reactive components. There
are some interesting kinetic results with pyrophosphorolysis which indicate that
such reversal is rapid when the DNA chain is being formed but is very slow or slight
once it has been formed. Before too long we'll have another look at the synthesis
of the hemophilus transforming DNA,

Sylvy and I are going to spend October in Japan and then go around the world in
November, The stimulus is an enzyme symposium in Tokyo. We're eager to have you and
Esther come down here and when I know my commitmentsfor next winter and spring more
precisely, I hope we can persuade you to visit us.

Thanks a lot for sending me the data about your medical genetics course, I
passed some of it on to key people here and will pushing for genetics instructions
for medical students at Stanford.

As ever,
Dh Maas

Arthur Kornberg

AK/o