title: Structure-function analysis of human protein O-linked mannose beta1,2-N-acetylglucosaminyltransferase 1, POMGnT1.
abstract: Protein O-linked mannose beta1,2-N-acetylglucosaminyltransferase 1 (POMGnT1) catalyzes the transfer of GlcNAc to O-mannose of glycoproteins. Mutations in the POMGnT1 gene cause a type of congenital muscular dystrophy called muscle-eye-brain disease (MEB). We evaluated several truncated mutants of POMGnT1 to determine the minimal catalytic domain. Deletions of 298 amino acids in the N-terminus and 9 amino acids in the C-terminus did not affect POMGnT1 activity, while larger deletions on either end abolished activity. These data indicate that the minimal catalytic domain is at least 353 amino acids. Single amino acid substitutions in the stem domain of POMGnT1 from MEB patients abolished the activity of the membrane-bound form but not the soluble form. This suggests that the stem domain of the soluble form of POMGnT1 is unnecessary for activity, but that some amino acids play a crucial role in the membrane-bound form.
authors.affiliation: Glycobiology Research Group, Tokyo Metropolitan Institute of Gerontology, Foundation for Research on Aging and Promotion of Human Welfare, 35-2 Sakaecho, Itabashi-ku, Tokyo 173-0015, Japan.
authors.forename: Keiko
authors.initials: K
authors.lastname: Akasaka-Manya
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Manya
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Kobayashi
authors.forename: Tatsushi
authors.initials: T
authors.lastname: Toda
authors.forename: Tamao
authors.initials: T
authors.lastname: Endo
mesh_terms: D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D001665:Binding Sites; D002384:Catalysis; D002460:Cell Line; D004789:Enzyme Activation; D006801:Humans; D007668:Kidney / Q000196:embryology / Q000201:enzymology*; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D017351:N-Acetylglucosaminyltransferases / Q000096:biosynthesis* / Q000737:chemistry*; D017434:Protein Structure, Tertiary; D013329:Structure-Activity Relationship
chemical_list: D017351:N-Acetylglucosaminyltransferases; C443106:protein O-mannose beta-1,2-N-acetylglucosaminyltransferase