April 12, 69.
Dr. F.H.C. Crick FRS
Dear Francis,
I was happy to receive your letter about a month ago. I am sorry for the delay -- Actually I found my commitments to West Coast this year in Feb. and the commotion of last fall all very trying. On returning from West Coast I came down with nervous exhaustion. I am feeling a bit better now and am soon leaving for Switzerland for a several weeks vacation.
Regarding your two points
(1) Ala-tRNA sequence. We ourselves had been worrying a lot about correctness of sequence around A-G (in so-called di-Hydro U region) and also as you may have seen, Carl Merril (Biopolymers, 6, 1727 (1968)) wants to add another G unit in the structure.
I have decided not to worry about these. The main aims at this stage as far as our synthetic work on yeast ala tRNA are (1) to work out the total chem.-enzymatic methodology for construction and characterization of DNA duplexes. (2) to learn to multiply these with DNA polymerase (3) to learn to transcribe the actual structure -- function, alliolionis [?] of gene etc etc will all be done (Whenever in the next decade (?) we get to it) with the E. coli tRNA gene which, as you know, we have also started on.
(2) Regarding UAG polymer -- What with turn-over of people and loss of my interest in repeating polymers, I find it difficult to maintain adequate checks and stocks on these. But, we could arrange to send informational amount of the DNA-polymer. Your people would have to multiply and then transcribe etc etc.
(3) Lastly Bob Bock tells me he has invited you to Gordon Conference. I hope you come.
with fond regards, Gobind.