title: Influence of substituents on the solution conformation of the exopolysaccharide produced by Pseudomonas 'gingeri' strain Pf9.
abstract: The influence of pyruvate ketals and acetyl groups on the conformational behaviour of the exopolysaccharide produced by Pseudomonas 'gingeri' strain Pf9 has been investigated experimentally through studies of intrinsic viscosity and circular dichroism experiments. A conformational variation was detected as a function of the ionic strength. Measurements carried out on the native polymer, as well as on both de-pyruvated and de-acetylated samples, suggested a critical role for the acetyl group on the solution conformation of the polysaccharide. Molecular mechanics calculations indicated the possibility of intramolecular hydrogen bonding between acetyl substituents on the mannose and the C(2)OH group of the preceding saccharidic unit. NMR linewidth measurements, carried out as a function of temperature, on the low molecular weight de-pyruvated sample indicated different polymeric backbone dynamics in aqueous solutions with respect to that observed in 0.3 M NaCl solutions.
authors.affiliation: Dipartimento di Biochimica, Biofisica e Chimica delle Macromolecole, Universita' di Trieste, Italy.
authors.forename: R
authors.initials: R
authors.lastname: Gianni
authors.forename: P
authors.initials: P
authors.lastname: Cescutti
authors.forename: M
authors.initials: M
authors.lastname: Bosco
authors.forename: W F
authors.initials: WF
authors.lastname: Fett
authors.forename: R
authors.initials: R
authors.lastname: Rizzo
mesh_terms: D002240:Carbohydrate Sequence; D003198:Computer Simulation; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D008968:Molecular Conformation; D008969:Molecular Sequence Data; D015394:Molecular Structure; D009994:Osmolar Concentration; D011134:Polysaccharides / Q000737:chemistry*; D011549:Pseudomonas / Q000737:chemistry*; D012965:Sodium Chloride / Q000378:metabolism; D013696:Temperature; D014783:Viscosity
chemical_list: D011134:Polysaccharides; D012965:Sodium Chloride