title: A novel type of highly negatively charged lipooligosaccharide from Pseudomonas stutzeri OX1 possessing two 4,6-O-(1-carboxy)-ethylidene residues in the outer core region.
abstract: Pseudomonas stutzeri OXI is a Gram-negative microorganism able to grow in media containing aromatic hydrocarbons. A novel lipo-oligosaccharide from P. stutzeri OX1 was isolated and characterized. For the first time, the presence of two moieties of 4,6-O-(1-carboxy)-ethylidene residues (pyruvic acid) was identified in a core region; these two residues were found to possess different absolute configuration. The structure of the oligosaccharide backbone was determined using either alkaline or acid hydrolysis. Alkaline treatment, aimed at recovering the complete carbohydrate backbone, was carried out by mild hydrazinolysis (de-O-acylation) followed by de-N-acylation using hot KOH. The lipo-oligosaccharide was also analyzed after acid treatment, attained by mild hydrolysis with acetic acid, to obtain information on the nature of the phosphate and acyl groups. The two resulting oligosaccharides were isolated by gel permeation chromatography, and investigated by compositional and methylation analyses, by MALDI mass spectrometry, and by 1H-, 31P- and 13C-NMR spectroscopy. These experiments led to the identification of the major oligosaccharide structure representative of core region-lipid A. All sugars are D-pyranoses and alpha-linked, if not stated otherwise. Based on the structure found, the hypothesis can be advanced that pyruvate residues are used to block elongation of the oligosaccharide chain. This would lead to a less hydrophilic cellular surface, indicating an adaptive response of P. sutzeri OX1 to a hydrocarbon-containing environment.
authors.affiliation: Dipartimento di Chimica Organica e Biochimica, Universita degli Studi di Napoli Federico II, Napoli, Italy.
authors.forename: Serena
authors.initials: S
authors.lastname: Leone
authors.forename: Viviana
authors.initials: V
authors.lastname: Izzo
authors.forename: Alba
authors.initials: A
authors.lastname: Silipo
authors.forename: Luisa
authors.initials: L
authors.lastname: Sturiale
authors.forename: Domenico
authors.initials: D
authors.lastname: Garozzo
authors.forename: Rosa
authors.initials: R
authors.lastname: Lanzetta
authors.forename: Michelangelo
authors.initials: M
authors.lastname: Parrilli
authors.forename: Antonio
authors.initials: A
authors.lastname: Molinaro
authors.forename: Alberto
authors.initials: A
authors.lastname: Di Donato
mesh_terms: D002240:Carbohydrate Sequence; D005030:Ethylenes / Q000737:chemistry*; D008070:Lipopolysaccharides / Q000737:chemistry*; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular; D044223:Pseudomonas stutzeri / Q000737:chemistry*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D005030:Ethylenes; D008070:Lipopolysaccharides; C023023:lipid-linked oligosaccharides; C036216:ethylene