title: Fractionation and structural characterization of LiCl-DMSO soluble hemicelluloses from tomato.
abstract: To prepare and explore the structure of native hemicellulose from tomato, extraction of the natively acetylated polysaccharides was achieved from partially depectinated cell walls by DMSO doped with LiCl. DEAE anion exchange chromatography of the LiCl-DMSO extract allowed the removal of residual acidic pectin and the isolation of acetylated glucuronoxylan. The hemicellulose neutral fraction from the anion exchanger was fractionated by size exclusion chromatography into xyloglucan (XyG) and galactoglucomannan (GgM) either as single major constituents or as mixtures of both. Residual hemicellulose in the cell wall was extracted by 4.0 M and not 1.0 M KOH. The fine structure of all LiCl-DMSO fractions and alkali extracts was assessed by coupling β-glucanase, β-mannanase and β-xylanase enzymatic degradations to the analysis of the resulting fragments by HPAEC and MALDI-TOF mass spectrometry. This approach revealed substitutions in part of the GgM fractions by pentose residues, presumably arabinose and/or xylose occurring in highly substituted block domains. It also demonstrated a different glucanase hydrolysis profile from 4.0 M KOH compared to LiCl-DMSO soluble fractions. The present extraction and purification scheme allow the recovery of several populations of acetylated hemicellulose families which emphasize the structural diversity and complexity of these polysaccharides.
authors.affiliation: INRA, UR 1268 Biopolymers, Interactions and Assemblies, rue de la Géraudière, F-44316 Nantes, France. cassor@nantes.inra.fr
authors.forename: Carole
authors.initials: C
authors.lastname: Assor
authors.forename: Bernard
authors.initials: B
authors.lastname: Quemener
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Vigouroux
authors.forename: Marc
authors.initials: M
authors.lastname: Lahaye
mesh_terms: D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D002458:Cell Fractionation / Q000379:methods; D002473:Cell Wall / Q000737:chemistry; D002852:Chromatography, Ion Exchange; D004121:Dimethyl Sulfoxide / Q000737:chemistry*; D043364:Endo-1,4-beta Xylanases / Q000737:chemistry; D005638:Fruit / Q000737:chemistry*; D006868:Hydrolysis; D018021:Lithium Chloride / Q000737:chemistry*; D018551:Solanum lycopersicum / Q000737:chemistry*; D008969:Molecular Sequence Data; D008970:Molecular Weight; D011134:Polysaccharides / Q000737:chemistry / Q000302:isolation & purification*; D012995:Solubility; D012997:Solvents / Q000737:chemistry*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D011134:Polysaccharides; D012997:Solvents; C007916:hemicellulose; D043364:Endo-1,4-beta Xylanases; D018021:Lithium Chloride; D004121:Dimethyl Sulfoxide