November 12, 1956

Professor KM. Heidelberger
Institute of Microbiology
Rutgers University
New Brunswick, N.J.

Dear Dr. Heidelberger:

While writiag a review on recombination gemtica, I have been catching
up on old reading, and am struck by my inability to find auch recent work
on the structure of the pasumoconcal capsular polysaccharides. An I wight
in thinking that type III 4s the only Sar for which a reasonably datailed
structure can be written (after Reaves & Goebel)? Or mve I overlooked
ejually pertinent studies on the composition and lini ges of other types?
I hope so, and that you can refer me to wre recent accounts of this field.
Now that the experimntal basis for genetic stuiies on the determination
of these substances is so well established, it seems to «m « pity that the
atruc tural and biosynthetic aspects have lost the primacy of interest that
thsy engaged some years ago. As far as I can tell, no one seems to have a
clus as to the iomediate precursors, though I suppose someone will come up
soon with another uridine—diphospho-conjugate!

Your help in this matter would be geataf greatly appreciated.

If Tam ask another question, Zamenhof has reported an the structure
of som of tho Hemophilus polysaccharides as poly-ribophosphates askin to
apurinic acids: is there any reason to dispute hia chins?

With best regards,

Yours sincerely,

“ /

ae, os
Jos, Lederbar’g ,
Profeasor of Genetics”

amet?