Tunicamycins

Scheme 18. Silicon-directed radical cyclization in Myers s synthesis of (+)-tunicamycin V (97).

The oligosaccharide GICjMangCGIcNAcjj is transferred from dolichol-P-P-oligosaccharide in a reaction catalyzed by oligosaccharide protein transferase, which is inhibited by tunicamycin. 

Tunicamycin Inhibits GIcNAc-P transferase, the enzyme catalyzing addition of GIcNAc to dolichol-P, the first step in the biosynthesis of oligosaccharide-P-P-dolichol... 

Houston, K.M. and Harnett, W. (1996) Prevention of attachment of phosphorylcholine to a major excretory-secretory product of Acanthocheilonema viteae using tunicamycin./oMraai of Parasitology 82, 320-324. 

Methylene sugars are versatile starting compounds for the synthesis of aromatic and hydroxymethyl C-glycosyl compounds (71) and of double-ended C-glycosyl compounds (70). The double bond undergoes 1,3-dipolar cycloadditions to give isoxazoline derivatives (71), such as that used as a model for the synthesis of tunicamycin. Also, reaction with iodonium sym-... 

Glycosyladon of the p62 afad El proteins is not needed for correct assembly in the ER, since in tunicamycin-treated cells, the assembly of these nonglycosylated proteins proceeds normally (Garoff and Schwarz, 1978). The drug tunicamycin blocks the assembly of the dolichol-linked oligosaccharide intermediate so that no transfer of oligosaccharides to nascent protein is possible (Tkasz and Lampen, 1975). 

As part of the investigation of the carbohydrate moieties of laccase III, we produced carbohydrate-depleted laccase III by the culture of C. versicolor with tunicamycin and by the selective cleavage of the carl hydrate chains with endoglycosidases. Laccases isolated from C. versicolor cultures which were treated with tunicamycin were analyzed... 

During the period of this research, the application of our approach to a tunicamycin derivative was undertaken. Though the work was not pursued far enough to obtain tunicamine or tunicaminyluracil, the scope of the general reaction was expanded somewhat, and some of... 

Interestingly, the selection of variants with reduced branching rates and enhanced strength of the cell wall results in a significantly enhanced production of erythromycin. This led Wardell et al. to search for the correlation between resistances to cell wall inhibitors bacitracin, tunicamycin and penicillin and production of the antibiotic. Significantly greater erythromycin titers were observed in the cultures of the tunicamycin- and penicillin-resistant mutants, whereas bacitracin-resistant mutant produced less antibiotic than the original strain. 

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