A Combination of Structural, Genetic, Phenotypic and Enzymatic Analyses Reveals the Importance of a Predicted Fucosyltransferase to Protein <i>O</i>-Glycosylation in the Bacteroidetes
Markus B. Tomek,
Bettina Janesch,
Matthias L. Braun,
Manfred Taschner,
Rudolf Figl,
Clemens Grünwald-Gruber,
Michael J. Coyne,
Markus Blaukopf,
Friedrich Altmann,
Paul Kosma,
Hanspeter Kählig,
Laurie E. Comstock,
Christina Schäffer
Affiliations
Markus B. Tomek
<i>NanoGlycobiology</i> Unit, Institute of Biologically Inspired Materials, Department of NanoBiotechnology, Universität für Bodenkultur Wien, Muthgasse 11, A-1190 Vienna, Austria
Bettina Janesch
<i>NanoGlycobiology</i> Unit, Institute of Biologically Inspired Materials, Department of NanoBiotechnology, Universität für Bodenkultur Wien, Muthgasse 11, A-1190 Vienna, Austria
Matthias L. Braun
<i>NanoGlycobiology</i> Unit, Institute of Biologically Inspired Materials, Department of NanoBiotechnology, Universität für Bodenkultur Wien, Muthgasse 11, A-1190 Vienna, Austria
Manfred Taschner
<i>NanoGlycobiology</i> Unit, Institute of Biologically Inspired Materials, Department of NanoBiotechnology, Universität für Bodenkultur Wien, Muthgasse 11, A-1190 Vienna, Austria
Rudolf Figl
Institute of Biochemistry, Department of Chemistry, Universität für Bodenkultur Wien, Muthgasse 18, A-1190 Vienna, Austria
Clemens Grünwald-Gruber
Institute of Biochemistry, Department of Chemistry, Universität für Bodenkultur Wien, Muthgasse 18, A-1190 Vienna, Austria
Michael J. Coyne
Department of Microbiology and the Duchossois Family Institute, University of Chicago, KCBD, 900 E. 57th Street, Chicago, IL 60637, USA
Markus Blaukopf
Institute of Organic Chemistry, Department of Chemistry, Universität für Bodenkultur Wien, Muthgasse 18, A-1190 Vienna, Austria
Friedrich Altmann
Institute of Biochemistry, Department of Chemistry, Universität für Bodenkultur Wien, Muthgasse 18, A-1190 Vienna, Austria
Paul Kosma
Institute of Organic Chemistry, Department of Chemistry, Universität für Bodenkultur Wien, Muthgasse 18, A-1190 Vienna, Austria
Hanspeter Kählig
Department of Organic Chemistry, Faculty of Chemistry, University of Vienna, Währinger Strasse 38, A-1090 Vienna, Austria
Laurie E. Comstock
Department of Microbiology and the Duchossois Family Institute, University of Chicago, KCBD, 900 E. 57th Street, Chicago, IL 60637, USA
Christina Schäffer
<i>NanoGlycobiology</i> Unit, Institute of Biologically Inspired Materials, Department of NanoBiotechnology, Universität für Bodenkultur Wien, Muthgasse 11, A-1190 Vienna, Austria
Diverse members of the Bacteroidetes phylum have general protein O-glycosylation systems that are essential for processes such as host colonization and pathogenesis. Here, we analyzed the function of a putative fucosyltransferase (FucT) family that is widely encoded in Bacteroidetes protein O-glycosylation genetic loci. We studied the FucT orthologs of three Bacteroidetes species—Tannerella forsythia, Bacteroides fragilis, and Pedobacter heparinus. To identify the linkage created by the FucT of B. fragilis, we elucidated the full structure of its nine-sugar O-glycan and found that l-fucose is linked β1,4 to glucose. Of the two fucose residues in the T. forsythia O-glycan, the fucose linked to the reducing-end galactose was shown by mutational analysis to be l-fucose. Despite the transfer of l-fucose to distinct hexose sugars in the B. fragilis and T. forsythia O-glycans, the FucT orthologs from B. fragilis, T. forsythia, and P. heparinus each cross-complement the B. fragilis ΔBF4306 and T. forsythia ΔTanf_01305 FucT mutants. In vitro enzymatic analyses showed relaxed acceptor specificity of the three enzymes, transferring l-fucose to various pNP-α-hexoses. Further, glycan structural analysis together with fucosidase assays indicated that the T. forsythia FucT links l-fucose α1,6 to galactose. Given the biological importance of fucosylated carbohydrates, these FucTs are promising candidates for synthetic glycobiology.
