title: Structure-activity relationship of the exopolysaccharide from a psychrophilic bacterium: A strategy for cryoprotection.
abstract: Microrganisms from sea ice, glacial and subglacial environments are currently under investigation due to their relevant ecological functions in these habitats, and to their potential biotechnological applications. The cold-adapted Colwellia psychrerythraea 34H produces extracellular polysaccharides with cryoprotection activity. We here describe the purification and detailed molecular primary and secondary structure of the exopolysaccharide (EPS) secreted by C. psychrerythraea 34H cells grown at 4°C. The structure was determined by chemical analysis and NMR. The trisaccharide repeating unit of the EPS is constituted by a N-acetyl quinovosamine unit and two residues of galacturonic acid both decorated with alanine. In addition, the EPS was tested in vitro showing a significant inhibitory effect on ice recrystallization. In-depth NMR and computational analysis suggest a pseudohelicoidal structure which seems to prevent the local tetrahedral order of the water molecules in the first hydration shell, and could be responsible of the inhibition of ice recrystallization. As cell cryopreservation is an essential tool in modern biotechnology and medicine, the observations reported in this paper could pave the way for a biotechnological application of Colwellia EPS.
authors.affiliation: Department of Chemical Sciences, University of Naples "Federico II", Complesso Universitario Monte S. Angelo, Via Cintia 4, 80126 Naples, Italy.
authors.forename: Angela
authors.initials: A
authors.lastname: Casillo
authors.affiliation: Department of Chemical Sciences, University of Naples "Federico II", Complesso Universitario Monte S. Angelo, Via Cintia 4, 80126 Naples, Italy.
authors.forename: Ermenegilda
authors.initials: E
authors.lastname: Parrilli
authors.affiliation: Department of Chemical Sciences, University of Naples "Federico II", Complesso Universitario Monte S. Angelo, Via Cintia 4, 80126 Naples, Italy.
authors.forename: Filomena
authors.initials: F
authors.lastname: Sannino
authors.affiliation: Department of Chemistry and Warwick Medical School, University of Warwick, Coventry CV4 7AL, UK.
authors.forename: Daniel E
authors.initials: DE
authors.lastname: Mitchell
authors.affiliation: Department of Chemistry and Warwick Medical School, University of Warwick, Coventry CV4 7AL, UK.
authors.forename: Matthew I
authors.initials: MI
authors.lastname: Gibson
authors.affiliation: Department of Chemical Sciences, University of Naples "Federico II", Complesso Universitario Monte S. Angelo, Via Cintia 4, 80126 Naples, Italy.
authors.forename: Gennaro
authors.initials: G
authors.lastname: Marino
authors.affiliation: Department of Chemical Sciences, University of Naples "Federico II", Complesso Universitario Monte S. Angelo, Via Cintia 4, 80126 Naples, Italy.
authors.forename: Rosa
authors.initials: R
authors.lastname: Lanzetta
authors.affiliation: Department of Biology, University of Naples "Federico II", Complesso Universitario Monte S. Angelo, Via Cintia 4, 80126 Naples, Italy.
authors.forename: Michelangelo
authors.initials: M
authors.lastname: Parrilli
authors.affiliation: DiSTABiF, Second University of Naples, Via Vivaldi 43, 81100 Caserta, Italy.
authors.forename: Sandro
authors.initials: S
authors.lastname: Cosconati
authors.affiliation: Department of Pharmacy, University of Naples "Federico II", Via D. Montesano, 49, 80131 Naples, Italy.
authors.forename: Ettore
authors.initials: E
authors.lastname: Novellino
authors.affiliation: Department of Pharmacy, University of Naples "Federico II", Via D. Montesano, 49, 80131 Naples, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Randazzo
authors.affiliation: Department of Chemical Sciences, University of Naples "Federico II", Complesso Universitario Monte S. Angelo, Via Cintia 4, 80126 Naples, Italy.
authors.forename: Maria L
authors.initials: ML
authors.lastname: Tutino
authors.affiliation: Department of Chemical Sciences, University of Naples "Federico II", Complesso Universitario Monte S. Angelo, Via Cintia 4, 80126 Naples, Italy. Electronic address: corsaro@unina.it.
authors.forename: M Michela
authors.initials: MM
authors.lastname: Corsaro
mesh_terms: D034241:Alteromonadaceae / Q000737:chemistry*; D003080:Cold Temperature; D003451:Cryoprotective Agents; D007053:Ice; D009682:Magnetic Resonance Spectroscopy; D011135:Polysaccharides, Bacterial / Q000737:chemistry / Q000302:isolation & purification*; D013329:Structure-Activity Relationship
chemical_list: D003451:Cryoprotective Agents; D007053:Ice; D011135:Polysaccharides, Bacterial
keywords: Alanine decoration; Cold-adaptation; Colwellia psychrerythraea 34H; Exopolymer; NMR spectroscopy