title: Fold recognition study of alpha3-galactosyltransferase and molecular modeling of the nucleotide sugar-binding domain.
abstract: The structure and fold of the enzyme responsible for the biosynthesis of the xenotransplantation antigen, namely pig alpha3 galactosyltransferase, has been studied by means of computational methods. Secondary structure predictions indicated that alpha3-galactosyltransferase and related protein family members, including blood group A and B transferases and Forssman synthase, are likely to consist of alternating alpha-helices and beta-strands. Fold recognition studies predicted that alpha3-galactosyltransferase shares the same fold as the T4 phage DNA-modifying enzyme beta-glucosyltransferase. This latter enzyme displays a strong structural resemblance with the core of glycogen phosphorylase b. By using the three-dimensional structure of beta-glucosyltransferase and of several glycogen phosphorylases, the nucleotide binding domain of pig alpha3-galactosyltransferase was built by knowledge-based methods. Both the UDP-galactose ligand and a divalent cation were included in the model during the refinement procedure. The final three-dimensional model is in agreement with our present knowledge of the biochemistry and mechanism of alpha3-galactosyltransferases.
authors.affiliation: Centre de Recherches sur les Macromolécules Végétales (associated with Université Joseph Fourier), CNRS, BP 53, F-38041 Grenoble Cedex 9, France.
authors.forename: A
authors.initials: A
authors.lastname: Imberty
authors.forename: C
authors.initials: C
authors.lastname: Monier
authors.forename: E
authors.initials: E
authors.lastname: Bettler
authors.forename: S
authors.initials: S
authors.lastname: Morera
authors.forename: P
authors.initials: P
authors.lastname: Freemont
authors.forename: M
authors.initials: M
authors.lastname: Sippl
authors.forename: H
authors.initials: H
authors.lastname: Flöckner
authors.forename: W
authors.initials: W
authors.lastname: Rüger
authors.forename: C
authors.initials: C
authors.lastname: Breton
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D020134:Catalytic Domain; D005700:Galactosyltransferases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D006801:Humans; D008024:Ligands; D008958:Models, Molecular; D008969:Molecular Sequence Data; D017510:Protein Folding; D017433:Protein Structure, Secondary; D017386:Sequence Homology, Amino Acid; D013552:Swine; D014531:Uridine Diphosphate Galactose / Q000378:metabolism
chemical_list: D008024:Ligands; D014531:Uridine Diphosphate Galactose; D005700:Galactosyltransferases; C047006:N-acetyllactosaminide alpha-1,3-galactosyltransferase