2nd April, 1965.
Dear Josh,
I have not yet seen Holley's paper in Science, but I think I follow most of what you say.
It is an old speculation that the S-RNA is so big because it may have to make a rather nicely balanced configurational change.  However, it was assumed that this would come about when the amino acid was added.  Your idea that it will only happen when the S-RIA combines with the correct codon is new to me.
I don't feel that there is anything hard to explain about the "Bernfield-Nirenberg" binding.  You only have to assume that in addition to the binding energy between the codon and the anti-codon there is a weak general binding of S-RNA and codon to the ribosomes.  I suspect that the binding between the codon and the anti-codon without the ribosome is too weak to be observable at all easily.
Basically I think your idea a good one, but it may be hard to prove it.
F. H. C. Crick