Letter from Arthur Kornberg to Robert L. Sinsheimer
Working to synthesize a viable DNA, Kornberg turned to the small bacterial viruses M13 and Phi X174. Biophysicist Robert Sinsheimer
at the California Institute of Technology had found that the single-stranded, circular Phi X174 virus DNA was converted to
a double helix after entering its E. coli host, and by itself was infective. In a previous letter, Kornberg had asked for
a sample of Sinsheimer's virus to start investigating its possible use as a replication template. This letter reported
on his initial results with the virus. It was from this virus that Kornberg was able to create an infective synthetic viral
DNA in 1967.
Number of Image Pages:
1 (60,142 Bytes)
1965-07-29 (July 29, 1965)
Sinsheimer, Robert L.
California Institute of Technology
Original Repository: Stanford University Libraries. Department of Special Collections and University Archives. Arthur Kornberg Papers
Reproduced with permission of Arthur Kornberg.
Medical Subject Headings (MeSH):
"Creating Life in the Test Tube," 1959-1970
Letter from Arthur Kornberg to Robert L. Sinsheimer (July 9, 1965)
July 29, 1965
Sankar Mitra finds that the OX sample you sent us primes as well as his M13 DNA. The enclosed graphs describe two experiments
with differing amounts of DNA polymerase. Here are some pertinent facts about this system. The DNA polymerase appears to
free the endonuclease under these conditions for an 80-minute incubation. There are no single strand breaks as judged by
release of tagged nucleotides (with ample opportunity for exonuclease II to act upon liberated 3' hydroxyl ends). The
M13 DNA primer (tritium H^3-labeled) remained resistant to exonuclease I after replication, whereas the P^32-labeled product
was almost completely degraded (the exo I action was imposed after alkaline denaturation). Also, in an alkaline sucrose gradient
the M13 DNA primer was not covalently linked to the product and sedimented with an S that suggested it had remained intact.
In view of the positive result with the OX DNA, I think it would be worth checking to see whether it remained intact after
serving as primer in the system. Tritium-labeled material with a specific activity in the neighborhood of 5 x 10^5 cpm/um
P would be suitable. Please let me know if you have any comments or suggestions that we could respond to.