title: Structure of Arabidopsis thaliana FUT1 Reveals a Variant of the GT-B Class Fold and Provides Insight into Xyloglucan Fucosylation.
abstract: The plant cell wall is a complex and dynamic network made mostly of cellulose, hemicelluloses, and pectins. Xyloglucan, the major hemicellulosic component in Arabidopsis thaliana, is biosynthesized in the Golgi apparatus by a series of glycan synthases and glycosyltransferases before export to the wall. A better understanding of the xyloglucan biosynthetic machinery will give clues toward engineering plants with improved wall properties or designing novel xyloglucan-based biomaterials. The xyloglucan-specific α2-fucosyltransferase FUT1 catalyzes the transfer of fucose from GDP-fucose to terminal galactosyl residues on xyloglucan side chains. Here, we present crystal structures of Arabidopsis FUT1 in its apoform and in a ternary complex with GDP and a xylo-oligosaccharide acceptor (named XLLG). Although FUT1 is clearly a member of the large GT-B fold family, like other fucosyltransferases of known structures, it contains a variant of the GT-B fold. In particular, it includes an extra C-terminal region that is part of the acceptor binding site. Our crystal structures support previous findings that FUT1 behaves as a functional dimer. Mutational studies and structure comparison with other fucosyltransferases suggest that FUT1 uses a SN2-like reaction mechanism similar to that of protein-O-fucosyltransferase 2. Thus, our results provide new insights into the mechanism of xyloglucan fucosylation in the Golgi.
authors.affiliation: Université Grenoble Alpes, 38400 Grenoble, France.|CNRS, CERMAV, 38041 Grenoble cedex 9, France.
authors.forename: Joana
authors.identifier: 0000-0003-2272-239X
authors.initials: J
authors.lastname: Rocha
authors.affiliation: Université Grenoble Alpes, 38400 Grenoble, France.|CNRS, CERMAV, 38041 Grenoble cedex 9, France.
authors.forename: Félix
authors.identifier: 0000-0001-7863-4327
authors.initials: F
authors.lastname: Cicéron
authors.affiliation: ESRF-The European Synchrotron, 38000 Grenoble, France.
authors.forename: Daniele
authors.identifier: 0000-0003-0391-8290
authors.initials: D
authors.lastname: de Sanctis
authors.affiliation: Université Grenoble Alpes, 38400 Grenoble, France.|CNRS, CERMAV, 38041 Grenoble cedex 9, France.
authors.forename: Mickael
authors.identifier: 0000-0002-4547-0132
authors.initials: M
authors.lastname: Lelimousin
authors.affiliation: Université Grenoble Alpes, 38400 Grenoble, France.|CNRS, CERMAV, 38041 Grenoble cedex 9, France.
authors.forename: Valérie
authors.initials: V
authors.lastname: Chazalet
authors.affiliation: Université Grenoble Alpes, 38400 Grenoble, France.|CNRS, CERMAV, 38041 Grenoble cedex 9, France.
authors.forename: Olivier
authors.identifier: 0000-0002-7633-1792
authors.initials: O
authors.lastname: Lerouxel
authors.affiliation: Université Grenoble Alpes, 38400 Grenoble, France breton@cermav.cnrs.fr.|CNRS, CERMAV, 38041 Grenoble cedex 9, France.
authors.forename: Christelle
authors.identifier: 0000-0003-3697-0677
authors.initials: C
authors.lastname: Breton
mesh_terms: D017360:Arabidopsis / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000378:metabolism*; D005647:Fucosyltransferases / Q000378:metabolism; D005936:Glucans / Q000378:metabolism*; D006056:Golgi Apparatus / Q000378:metabolism; D006154:Guanosine Diphosphate Fucose / Q000378:metabolism; D014990:Xylans / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D005936:Glucans; D014990:Xylans; D006154:Guanosine Diphosphate Fucose; C029353:xyloglucan; D005647:Fucosyltransferases; C070983:xyloglucan 2-fucosyltransferase