title: Functional characterization of Drosophila melanogaster peptide O-xylosyltransferase, the key enzyme for proteoglycan chain initiation and member of the core 2/I N-acetylglucosaminyltransferase family.
abstract: Chondroitin and heparan sulfates are essential players in animal development and are synthesized by a series of glycosyltransferases, the first of which is UDP-alpha-D-xylose:proteoglycan core protein beta-D-xylosyltransferase (EC ). In the present study, a Drosophila melanogaster gene (CG17771), previously designated as a homologue of core 2 and I beta1,6-N-acetylglucosaminyltransferases, was shown to encode an active peptide O-xylosyltransferase. A novel coupled assay using matrix-assisted laser desorption ionization time-of-flight mass spectrometry demonstrated transfer of xylose to the peptide DDDSIEGSGGR. Analysis of sequences of various peptide O-xylosyltransferase and beta1,6-N-acetylglucosaminyltransferase sequences indicates that they are members of a large multifunctional protein family with a range of roles in beta-glycosylation of either peptide or glycan substrates. Because in contrast to mammals, there is only one fly peptide O-xylosyltransferase gene, it is anticipated that, given the key roles of proteoglycans, the hereby designated oxt gene is essential for viability.
authors.affiliation: Glycobiology Division, Institut für Chemie, Universität für Bodenkultur, Muthgasse 18, A-1190 Wien, Austria.
authors.forename: Iain B H
authors.initials: IB
authors.lastname: Wilson
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D018076:DNA, Complementary / Q000378:metabolism; D004330:Drosophila; D004331:Drosophila melanogaster / Q000201:enzymology*; D020224:Expressed Sequence Tags; D016695:Glycosyltransferases / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D017351:N-Acetylglucosaminyltransferases / Q000737:chemistry* / Q000378:metabolism; D010430:Pentosyltransferases / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*; D010455:Peptides / Q000737:chemistry; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D011994:Recombinant Proteins / Q000378:metabolism; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D014994:Xylose / Q000737:chemistry; D000097608:UDP Xylose-Protein Xylosyltransferase
chemical_list: D018076:DNA, Complementary; D016695:Glycosyltransferases; D017351:N-Acetylglucosaminyltransferases; D010430:Pentosyltransferases; D010455:Peptides; D011994:Recombinant Proteins; D014994:Xylose; D000097608:UDP Xylose-Protein Xylosyltransferase; C037649:N-acetyllactosaminide beta-1,6-N-acetylglucosaminyltransferase