All in One:Leishmania majorSTT3 Proteins Substitute for the Whole Oligosaccharyltransferase Complex inSaccharomyces cerevisiae
Open Access
- 1 September 2008
- journal article
- Published by American Society for Cell Biology (ASCB) in Molecular Biology of the Cell
- Vol. 19 (9), 3758-3768
- https://doi.org/10.1091/mbc.e08-05-0467
Abstract
The transfer of lipid-linked oligosaccharide to asparagine residues of polypeptide chains is catalyzed by oligosaccharyltransferase (OTase). In most eukaryotes, OTase is a hetero-oligomeric complex composed of eight different proteins, in which the STT3 component is believed to be the catalytic subunit. In the parasitic protozoa Leishmania major, four STT3 paralogues, but no homologues to the other OTase components seem to be encoded in the genome. We expressed each of the four L. major STT3 proteins individually in Saccharomyces cerevisiae and found that three of them, LmSTT3A, LmSTT3B, and LmSTT3D, were able to complement a deletion of the yeast STT3 locus. Furthermore, LmSTT3D expression suppressed the lethal phenotype of single and double deletions in genes encoding other essential OTase subunits. LmSTT3 proteins did not incorporate into the yeast OTase complex but formed a homodimeric enzyme, capable of replacing the endogenous, multimeric enzyme of the yeast cell. Therefore, these protozoan OTases resemble the prokaryotic enzymes with respect to their architecture, but they used substrates typical for eukaryotic cells: N-X-S/T sequons in proteins and dolicholpyrophosphate-linked high mannose oligosaccharides.Keywords
This publication has 40 references indexed in Scilit:
- Dolichol-linked oligosaccharide selection by the oligosaccharyltransferase in protist and fungal organismsThe Journal of cell biology, 2007
- Preferential transfer of the complete glycan is determined by the oligosaccharyltransferase complex and not by the catalytic subunitProceedings of the National Academy of Sciences of the United States of America, 2006
- Definition of the bacterial N-glycosylation site consensus sequenceThe EMBO Journal, 2006
- The Genome of the Kinetoplastid Parasite, Leishmania majorScience, 2005
- The Genome of the African Trypanosome Trypanosoma bruceiScience, 2005
- N-Linked Glycosylation in Campylobacter jejuni and Its Functional Transfer into E. coliScience, 2002
- Secretory Pathway of Trypanosomatid ParasitesMicrobiology and Molecular Biology Reviews, 2002
- Getting started with yeastMethods in Enzymology, 2002
- Protein glycosylation in yeastBiochimica et Biophysica Acta (BBA) - Reviews on Biomembranes, 1987
- Cleavage of Structural Proteins during the Assembly of the Head of Bacteriophage T4Nature, 1970