title: Structural characterization of neutral and anionic glucans from Mesorhizobium loti.
abstract: The periplasmic glucans of Mesorhizobium loti were isolated and separated into fractions according to their acidity. NMR spectroscopy confirmed their backbone structure to be a cyclic beta-(1-->2)-d-glucan as in the case of other rhizobia, and revealed no non-glycosidic substituents in the neutral fraction, and glycerophosphoryl and succinyl residues as major and minor substituents, respectively, in the anionic fractions. MALDI-TOF mass spectrometry showed that the anionic glucans contain one, two, or three such substituents per molecule according to their acidity, and, in contrast, that all the anionic subfractions have a similar size distribution to that of the neutral glucans, where molecules composed of 20-24 glucosyl residues are predominant. These results clarify the periplasmic glucan composition in terms of charge-to-mass ratios in M. loti cells.
authors.affiliation: Graduate School of Life Sciences, Tohoku University, Katahira, Aoba-ku, Sendai 980-8577, Japan.
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Kawaharada
authors.forename: Hiromasa
authors.initials: H
authors.lastname: Kiyota
authors.forename: Shima
authors.initials: S
authors.lastname: Eda
authors.forename: Kiwamu
authors.initials: K
authors.lastname: Minamisawa
authors.forename: Hisayuki
authors.initials: H
authors.lastname: Mitsui
mesh_terms: D020561:Alphaproteobacteria / Q000737:chemistry*; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D005936:Glucans / Q000737:chemistry* / Q000302:isolation & purification; D005994:Glycerophosphates / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D019802:Succinic Acid / Q000737:chemistry
chemical_list: D005936:Glucans; D005994:Glycerophosphates; D019802:Succinic Acid