title: Structural investigation of an exopolysaccharide substituted with a lactyl ether group produced by Raoultella terrigena Ez-555-6 isolated in the Chernobyl exclusion zone.
abstract: Raoultella terrigena strain Ez-555-6, isolated from a root nodule of Medicago sativa harvested in the Chernobyl exclusion zone, produces a non-referenced high-molecular-mass exopolysaccharide (EPS). The structure of this EPS was determined using a combination approach including monosaccharide composition (GLC-FID, HPAEC-PAD), determination of glycosylation sites (GLC-EIMS) and 1D/2D NMR ((1)H, (13)C) and ESIMS (HR, MS/MS) studies of oligosaccharides obtained from mild acid hydrolysis. The EPS was found to be a charged pentasaccharide with a repeating unit composed of D-galactose, D-glucose, D-mannose and D-glucuronic acid (1:2:1:1). Lactic acid and O-acetyl substituents were localized on galactose and glucose residues, respectively, as presented in the following structure:
authors.affiliation: Laboratoire des Polysaccharides Microbiens et Végétaux, Université de Picardie Jules Verne, IUT d'Amiens, Avenue des Facultés, Amiens, France.
authors.forename: M
authors.initials: M
authors.lastname: Pillon
authors.forename: C
authors.initials: C
authors.lastname: Pau-Roblot
authors.forename: V
authors.initials: V
authors.lastname: Lequart
authors.forename: S
authors.initials: S
authors.lastname: Pilard
authors.forename: B
authors.initials: B
authors.lastname: Courtois
authors.forename: J
authors.initials: J
authors.lastname: Courtois
authors.forename: N
authors.initials: N
authors.lastname: Pawlicki-Jullian
mesh_terms: D002240:Carbohydrate Sequence; D047852:Chernobyl Nuclear Accident; D004755:Enterobacteriaceae / Q000737:chemistry*; D004987:Ethers / Q000737:chemistry*; D006027:Glycosides / Q000737:chemistry; D006868:Hydrolysis; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D009005:Monosaccharides / Q000737:chemistry; D011135:Polysaccharides, Bacterial / Q000737:chemistry* / Q000302:isolation & purification*; D021241:Spectrometry, Mass, Electrospray Ionization; D053719:Tandem Mass Spectrometry
chemical_list: D004987:Ethers; D006027:Glycosides; D009005:Monosaccharides; D011135:Polysaccharides, Bacterial