Original Repository: Stanford University Libraries. Department of Special Collections and University Archives. Paul Berg Papers
Reproduced with permission of Armin D. Kaiser.
Medical Subject Headings (MeSH):
Protein Synthesis, Tumor Viruses, and Recombinant DNA, 1959-1975
Letter from Paul Berg to Armin D. Kaiser (March 31, 1965)
Today I heard a lecture given by Phillips on the structure of hen's egg white lysozyme. They have determined the structure
by x-ray diffraction to 2 angstroms resolution. With some help from the known amino acid sequence they have traced the course
of the polypeptide chain and have been able to construct an acceptable model.
Only about 50 of the residues are in alpha-helix and one end of the molecule is very complicated. There is a cleft in the
molecule near that end into which three different inhibitors are known to bind. They can diffuse the inhibitor into the enzyme
crystals without change in the crystal structure and have located the inhibitors to 6 angstroms resolution. They will be able
now to locate them to 2 angstroms resolution. H-acetyl glucosamine and chitobiose both bind at the same place in the cleft
and penicillin, the third inhibitor, binds higher up in the cleft.
There is only one histidine in lysozyme and it isn't in the cleft. There are 3 tryptophan residues in the cleft, a serine,
and a couple of aspartics. The structure looks as though it might be able to spread apart at the cleft.
Phillips put their model out for display and it was such an exciting thing for me to look down the gullet of an enzyme that
I had to tell you about it.
Mary sends her greetings and says she will write to Milly soon.