Tunicamycin structure

The liposidomycins are a family of novel lipid-containing nucleoside antibiotics that were found in the culture filtrate and mycelia of Streptomyces griseoporeus These antibiotics, which have unique biological activity and structures, inhibit the formation of the lipid intermediate in bacterial peptidoglycan synthesis three times more than does tunicamycin and have extremely high specificity. The structures of liposidomycins B (1) and C were proposed on the basis of degradation and spectroscopic studies. They are identical except for slight variations in the lipid portion. 

Ribosylation of isopropylideneuridine and subsequent manipulations led to the synthesis of 170 (R = H), which constitutes a part-structure of the liposidomycin class of antibiotics. The two isomers of 170 (R = CH2OH) were also prepared in synthetic sequences that involved ribosylation of D-allofuranose and L-talofuranose derivatives at 0-5, with introduction of uracil at a late stage. Molecular modelling was carried out of both liposidomycins and tunicamycin with the UDP-iV-acetylmuramic acid-pentapeptide that is the substrate for the enzyme (translocase) in bacterial cell wall biosynthesis that the antibiotics inhibit, and, in accordance with the predictions, only the 5-isomer of 170 (R = CH2OH) was a good inhibitor. ... 

Figure 4.10 The Structure of the Major Component of Tunicamycin — Variation in the Fatty Acyl Chain Occurs.

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