title: Pseudoglycosyltransferase catalyzes nonglycosidic C-N coupling in validamycin a biosynthesis.
abstract: Glycosyltransferases are ubiquitous in nature. They catalyze a glycosidic bond formation between sugar donors and sugar or nonsugar acceptors to produce oligo/polysaccharides, glycoproteins, glycolipids, glycosylated natural products, and other sugar-containing entities. However, a trehalose 6-phosphate synthase-like protein has been found to catalyze an unprecedented nonglycosidic C-N bond formation in the biosynthesis of the aminocyclitol antibiotic validamycin A. This dedicated 'pseudoglycosyltransferase' catalyzes a condensation between GDP-valienol and validamine 7-phosphate to give validoxylamine A 7'-phosphate with net retention of the 'anomeric' configuration of the donor cyclitol in the product. The enzyme operates in sequence with a phosphatase, which dephosphorylates validoxylamine A 7'-phosphate to validoxylamine A.
authors.affiliation: Department of Pharmaceutical Sciences, Oregon State University, Corvallis, Oregon 97331-3507, USA.
authors.forename: Shumpei
authors.initials: S
authors.lastname: Asamizu
authors.forename: Jongtae
authors.initials: J
authors.lastname: Yang
authors.forename: Khaled H
authors.initials: KH
authors.lastname: Almabruk
authors.forename: Taifo
authors.initials: T
authors.lastname: Mahmud
mesh_terms: D055162:Biocatalysis; D005964:Glucosyltransferases / Q000737:chemistry / Q000378:metabolism*; D007294:Inositol / Q000031:analogs & derivatives / Q000096:biosynthesis / Q000737:chemistry; D008968:Molecular Conformation; D013237:Stereoisomerism
chemical_list: D007294:Inositol; C003749:validamycins; D005964:Glucosyltransferases