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Oxidoreductase activity of oligosaccharyltransferase subunits Ost3p and Ost6p defines site-specific glycosylation efficiency.
- Source :
-
Proceedings of the National Academy of Sciences of the United States of America [Proc Natl Acad Sci U S A] 2009 Jul 07; Vol. 106 (27), pp. 11061-6. Date of Electronic Publication: 2009 Jun 23. - Publication Year :
- 2009
-
Abstract
- Asparagine-linked glycosylation is a common posttranslational modification of diverse secretory and membrane proteins in eukaryotes, where it is catalyzed by the multiprotein complex oligosaccharyltransferase. The functions of the protein subunits of oligoasccharyltransferase, apart from the catalytic Stt3p, are ill defined. Here we describe functional and structural investigations of the Ost3/6p components of the yeast enzyme. Genetic, biochemical and structural analyses of the lumenal domain of Ost6p revealed oxidoreductase activity mediated by a thioredoxin-like fold with a distinctive active-site loop that changed conformation with redox state. We found that mutation of the active-site cysteine residues of Ost6p and its paralogue Ost3p affected the glycosylation efficiency of a subset of glycosylation sites. Our results show that eukaryotic oligosaccharyltransferase is a multifunctional enzyme that acts at the crossroads of protein modification and protein folding.
- Subjects :
- Amino Acid Motifs
Catalytic Domain
Glycosylation
Models, Biological
Models, Molecular
Peptides metabolism
Protein Binding
Protein Structure, Secondary
Sulfhydryl Compounds metabolism
Hexosyltransferases metabolism
Membrane Proteins metabolism
Oxidoreductases metabolism
Protein Subunits metabolism
Saccharomyces cerevisiae enzymology
Saccharomyces cerevisiae Proteins metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 1091-6490
- Volume :
- 106
- Issue :
- 27
- Database :
- MEDLINE
- Journal :
- Proceedings of the National Academy of Sciences of the United States of America
- Publication Type :
- Academic Journal
- Accession number :
- 19549845
- Full Text :
- https://doi.org/10.1073/pnas.0812515106