January 3, 1967
Dear Francis:
Thanks for your letters of December 15th and 22nd.
I am now planning to come out to La Jolla for a few days. I shall probably be there from the 1st to the 4th of February.* I shall also write to Les and Ed Lennox, who is my point of contact at the moment, to see if C. Yanofsky can also come out there during those days.
The work on phenylalanine tRNA (yeast) is now finished and we are writing up a summary of the total work for publication.  There is no modification in the structure except for deletion of one base (C) (7th from acceptor end) that I told you about last October.  We are also writing up work on initiation codons as studied with repeating polymers.  Poly GUA also seems to recognize f-met at low Mg++.  At high Mg++ the polymer incorporates ser and val, as you know, but at 0.004 M we get valine incorporation only and this is dependent on addition of f-met.  This stimulation, however, is low (5-fold over the background); at 0.01 M Mg++ valine incorporation, in the absence or presence of f-met, is about 140-150 fold, so the recognition is weak.
Sincerely yours,
H. Gobind Khorana
*arriving there on Jan 31st.