title: Expression and characterization of the first snail-derived UDP-N-acetyl-α-D-galactosamine:polypeptide N-acetylgalactosaminyltransferase.
abstract: UDP-GalNAc:polypeptide GalNAc transferase (ppGalNAcT; EC 2.4.1.41) catalyzes the first step in mucin-type O-glycosylation. To date, several members of this large enzyme family have been analyzed in detail. In this study we present cloning, expression and characterization of the first representative of this type of glycosyltransferase from mollusk origin, namely from Biomphalaria glabrata. The full length sequence of the respective gene was obtained by screening of a cDNA library using homology-based PCR. The entire gene codes for a protein consisting of 600 amino acids comprising the features of a typical type II membrane protein containing a cytoplasmic tail at the N-terminus, a transmembrane and a catalytic domain as well as a ricin-like motif at the C-terminus. Sequence comparison with ppGalNAcTs from various species revealed high similarities in terms of structural architecture. The enzyme is O-glycosylated but does not have any putative N-glycosylation sites. All four tested acceptor peptides were functional substrates, with Muc2 being the best one. Further biochemical parameters tested, confirmed a close relationship to the family of yet known ppGalNAcTs.
authors.affiliation: Department of Chemistry, University of Natural Resources and Life Sciences, Vienna, Muthgasse 18, 1190, Vienna, Austria.
authors.forename: Christopher
authors.initials: C
authors.lastname: Taus
authors.forename: Chantal
authors.initials: C
authors.lastname: Lucini
authors.forename: Takeshi
authors.initials: T
authors.lastname: Sato
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Furukawa
authors.forename: Reingard
authors.initials: R
authors.lastname: Grabherr
authors.forename: Erika
authors.initials: E
authors.lastname: Staudacher
mesh_terms: D000818:Animals; D001700:Biomphalaria / Q000201:enzymology*; D017350:N-Acetylgalactosaminyltransferases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D061987:Sf9 Cells; D018411:Spodoptera; D000097763:Polypeptide N-acetylgalactosaminyltransferase
chemical_list: D017350:N-Acetylgalactosaminyltransferases; D000097763:Polypeptide N-acetylgalactosaminyltransferase