13th January, 1971.
Dear Dr. Nathans,
Lionel Crawford and I have recently developed a procedure for strand separation of Form II SV40 DNA which utilizes synthetic polynucleotides as per Szybalski. We are planning to study single stranded viral DNA in a coupled in vitro protein synthesis system and would very much like to do experiments with a unique population of linear molecules. Your recent observations with B-restriction enzyme of E. coli suggests that it could provide such a population of DNA molecules. Would it be possible to obtain from you a sample of the B-enzyme for use in our system. Should you be able to spare a sample we will be happy to cover all transportation expenses.
Thanking you in advance.
Yours sincerely,
D. Ward.