Thymidine Diphosphate 4-acetamido-4, 6-dideoxyhexoses. I. Enzymatic Synthesis by Strains of Escherichia Coli.

Several thymidine diphosphate sugar compounds have been isolated from Escherichia coli strains and other microorganisms. TDP-X, isolated from E. coli strain Y-10 by Strominger and Scott (1) and from other strains of E. coli (2) and TDP-X2 isolated from E. coli strain B, by Okazaki, Okazaki, and Kuriki (3) are unusual acetamido sugar-containing nucleotides (4). The sugars are 4-acetamido-4,6-dideoxyhexoses; the structure of the sugar Xz has been investigated by Okazaki, Okazaki, and Suzuki in Japan (5) and that of X by Dr. David Dietzler in this laboratory (6). The data obtained are consistent with the configuration of n-glucose for Xz and of n-galactose for X with respect to C-4 to C-6. Since nothing is known about the configuration of C-2 and C-3 in these sugars, the following structural formulas are tentative assignments.