title: The inner core region of Yersinia enterocolitica Ye75R (0:3) lipopolysaccharide.
abstract: The inner-core region of the lipopolysaccharide of an UDPGalNAc-4-epimerase-deficient mutant of Yersinia enterocolitica 0:3, designated as Ye75R, was investigated using methylation analysis, 1D-13C-NMR and 2D-13C-NMR and 1H-NMR, as well as 31P-NMR, fast-atom-bombardment mass spectrometry (FAB MS) and FAB MS/MS in positive and negative modes. The isolated core heptasaccharide (OS) was composed of 2 units D-glucose, 3 units LD-heptose and 1 unit each of DD-heptose and 3-deoxy-D-manno-octulosonic acid. Methylation analysis indicated that OS was highly branched with terminal location of the two glucoses and the DD-heptose unit, which was partially (to about 40%) phosphorylated at C7. These combined studies allowed us to formulate the structure of the inner core region as shown in Scheme 1. The substitution of the 7-position of the terminally linked DD-heptose unit by phosphate could be recognized by MS characterization of permethylated DD-heptose-7-phosphate (alditol acetate) and the extent of the substitution by the ratio of the two well separated 1H signals of DD-heptose in 500-MHz 1H-NMR. Negative FAB MS of OS also indicated the presence of smaller amounts of two hexasaccharides, differing from OS in lacking either one terminal unit of D-glucose or of the terminal DD-heptose, and additionally of a pentasaccharide lacking two heptosyl units, namely the terminal DD-heptose and and the subterminal LD-heptose. The presence of the smaller oligosaccharides in the OS fraction was also recognized by the methylation analysis.
authors.affiliation: Instytut Mikrobiologii, Uniwersytet Lódzki, Poland.
authors.forename: J
authors.initials: J
authors.lastname: Radziejewska-Lebrecht
authors.forename: A S
authors.initials: AS
authors.lastname: Shashkov
authors.forename: V
authors.initials: V
authors.lastname: Stroobant
authors.forename: K
authors.initials: K
authors.lastname: Wartenberg
authors.forename: C
authors.initials: C
authors.lastname: Warth
authors.forename: H
authors.initials: H
authors.lastname: Mayer
mesh_terms: D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D008401:Gas Chromatography-Mass Spectrometry; D008070:Lipopolysaccharides / Q000032:analysis / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008745:Methylation; D008969:Molecular Sequence Data; D009154:Mutation; D009844:Oligosaccharides / Q000032:analysis / Q000737:chemistry; D010710:Phosphates / Q000032:analysis; D016339:Spectrometry, Mass, Fast Atom Bombardment; D015008:Yersinia enterocolitica / Q000737:chemistry*
chemical_list: D008070:Lipopolysaccharides; D009844:Oligosaccharides; D010710:Phosphates