EVOLUTION AND DIVERSITY OF EUKARYOTIC GLYCOSYLATION

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This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. While Saccharomyces cerevisiae has been a good model for human N- and O-linked glycosylation and GPI-anchor synthesis, most of the evolution and diversity in protein glycosylation exists among deeply divergent protists. Glycosylation of kinetoplastids (e.g. Trypanosoma sp. and Leishmania sp.) has been extensively studied, but glycosylation of microaerophilic protists (Trichomonas vaginalis, Giardia lamblia (GI), and Entamoeba histolytica (Eh) are not well studied. Whole genome sequences that predict the total proteins (proteome) are now available for all of these protist species. Preliminary evidence of the diversity of eukaryotic glycosylation based upon our bioinformatics/ experimental approach predict that Eh and Tv make abbreviated dolichol-linked N-glycan precursors. Preliminary experiments demonstrate that Eh and Tv do, indeed, synthesize abbreviated dolichol-linked N-glycan precursors. Therefore, the truncated precursors will likely be the starting point for any subsequent modifications. However, reverse genetics may not predict modifications that are specific to the niche of a given protest and, therefore, structural studies will be conducted to determine if the oligosaccharides are modified by additional Golgi or Golgi-like modifications or if they are simply truncated as found in, Trypanosomes.