The Role of Dolichol in Protein Glycosylation

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DESCRIPTION (provided by applicant): The role of dolichol in the dolichol linked gylcosylation pathway is unknown. This essential pathway is responsible for the high fidelity production of the dolichol-linked tetradecasaccharide, Dol-PP- (GlcNAc)2Man9GIc3, in the endoplasmic reticulum (ER). The tetradecasaccharide is then transferred en block, via the enzyme oligosaccharyltransferase to nascent proteins being translated in the rough ER. It has been proposed that dolichol, a large polyisoprenoid lipid, facilitates the production of the oligosaccaride by increasing membrane fluidity. It has also been proposed that dolichol acts to anchor the developing oligosaccaride to the ER membrane, thereby facilitating transfer between the membrane bound enzymes that catalyze the additions of the saccharides, the asparagine-linked gylcoslyation enzymes (ALG). These hypotheses, as well as what the role of dolichol rich membranes have in the association of the ALG enzymes, will be tested. The experiments are designed using state of the art techniques at the interface between chemistry and biology. Initially work will be on isolated steps of the pathway and will advance to investigating a sequence of steps. Biophysical, chemical and biological techniques will be used.