Molecular basis for galactosylation of core fucose residues in invertebrates: identification of caenorhabditis elegans N-glycan core alpha1,6-fucoside beta1,4-galactosyltransferase GALT-1 as a member of a novel glycosyltransferase family.
Galectin CGL2 from the ink cap mushroom Coprinopsis cinerea displays toxicity toward the model nematode Caenorhabditis elegans. A mutation in a putative glycosyltransferase-encoding gene resulted in a CGL2-resistant C. elegans strain characterized by N-glycans lacking the beta1,4-galactoside linked to the alpha1,6-linked core fucose. Expression of the corresponding GALT-1 protein in insect cells was used to demonstrate a manganese-dependent galactosyltransferase activity. In vitro, the GALT-1 enzyme showed strong selectivity for acceptors with alpha1,6-linked N-glycan core fucosides and required Golgi- dependent modifications on the oligosaccharide antennae for optimal synthesis of the Gal-beta1,4-fucose structure. Phylogenetic analysis of the GALT-1 protein sequence identified a novel glycosyltransferase family (GT92) with members widespread among eukarya but absent in mammals.
Institute of Microbiology, ETH Zürich, Wolfgang-Pauli-Strasse 10, CH-8093 Zürich, Switzerland.
Alexander
A
Titz
Institute of Molecular Biology, University of Zürich, CH-8057 Zürich, Switzerland.
Alex
A
Butschi
Architecture et Fonction des Macromolécules Biologiques, UMR6098, CNRS and Universités Aix-Marseille I and II, 13288 Marseille, France.
Bernard
B
Henrissat
Institute of Microbiology, ETH Zürich, Wolfgang-Pauli-Strasse 10, CH-8093 Zürich, Switzerland.
Yao-Yun
YY
Fan
Institute of Physiology, University of Zürich, CH-8057 Zürich, Switzerland.
Thierry
T
Hennet
VetOMICS Core Facility for Proteomics and Metabolomics Studies, University of Veterinary Medicine, A-1210 Vienna, Austria.
Ebrahim
E
Razzazi-Fazeli
Institute of Molecular Biology, University of Zürich, CH-8057 Zürich, Switzerland.
Michael O
MO
Hengartner
Department für Chemie, Universität für Bodenkultur, A-1190 Vienna, Austria.
Iain B H
IBH
Wilson
Institute of Microbiology, ETH Zürich, Wolfgang-Pauli-Strasse 10, CH-8093 Zürich, Switzerland.
Markus
M
Künzler
Institute of Microbiology, ETH Zürich, Wolfgang-Pauli-Strasse 10, CH-8093 Zürich, Switzerland. Electronic address: markus.aebi@micro.biol.ethz.ch.
Markus
M
Aebi
D000818:Animals; D017173:Caenorhabditis elegans / Q000201:enzymology* / Q000235:genetics; D005643:Fucose / Q000235:genetics / Q000378:metabolism; D005700:Galactosyltransferases / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D009844:Oligosaccharides / Q000096:biosynthesis* / Q000235:genetics; D010802:Phylogeny; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D013379:Substrate Specificity / Q000502:physiology
D009844:Oligosaccharides; D011994:Recombinant Proteins; D005643:Fucose; D005700:Galactosyltransferases