Investigating the pathway of asparagine-linked glycoprotein biosynthesis

The biosynthesis of asparagine-linked glycoproteins, highly conserved throughout all eukaryotes, requires a dolichylpyrophosphate-linked tetradecasaccharide precursor (Dol-PP-GlcNAc2Man9Glc3), from which the tetradecasaccharide is transferred co-translationally to nascent polypeptides in the lumen of the ER by the multimeric membrane-bound enzyme, oligosaccharyl transferase (OT). The saccharide donor is assembled by a series of membrane-bound enzymes, which together comprise the dolichol pathway. Despite over two decades of genetic and bioinformatics approaches that have identified the vast majority of dolichol pathway genes in yeast, the roles of two mannosyltransferases in the pathway, Alg2 and Algl 1, remained ambiguous. This thesis describes the biochemical studies that were carried out to clarify these roles. The substrate specificity of Algl, the first mannosyltransferase in the pathway, was studied, and this enzyme was also used as a tool to prepare Man1 ,4-GlcNAc2-PP-Dol from synthetic GlcNAc2-PP-Dol. Access to this trisaccharide intermediate facilitated the characterization of Alg2 function, proposed to be involved in addition of the second and/or third mannose.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Chemistry.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2006

Author dc:creator

• O'Reilly, Mary K. (Mary Katherine)

Advisor dc:contributor.advisor

• Barbara Imperiali.

• Chemistry.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/36265

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/36265