Original Repository: Stanford University Libraries. Department of Special Collections and University Archives. Paul Berg Papers
Reproduced with permission of Paul Berg.
Medical Subject Headings (MeSH):
Protein Synthesis, Tumor Viruses, and Recombinant DNA, 1959-1975
Letter from Robert Langridge to Paul Berg (January 4, 1965)
January 11, 1965
Had you been here when I read your letter, you could have helped pick me up off the floor. Although we think have a much
improved method for fractionating t-RNA, we have yet to produce any "pure" specific RNA chain. I have estimated that
to produce 100 mg of pure t-RNA for your preliminary X-ray work would take approximately 15 gm of starting material and literally
thousands of man-hours of work. Consider for example that most t-RNA's represent of the order of less than 5% of the population
and even this is a mixture of 3 - 5 different "isomers" of that amino acid-specific class. For the purposes you want,
each of these classes has to be separated.
I hope that we can progress to the point where your requirements could considered realistic, but unfortunately at the moment
we've not gotten that far.
I relayed your request to Mike for a copy of his paper. My trip to Boston was much too short and I'm sorry I didn't
get a chance to talk to you and many of the others I'd hoped to see. The next trip will certainly be for a longer time.