Structural characterization of neutral and anionic glucans from Mesorhizobium loti.
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.
Kawaharada
Yasuyuki
Y
Graduate School of Life Sciences, Tohoku University, Katahira, Aoba-ku, Sendai 980-8577, Japan.
Kiyota
Hiromasa
H
Eda
Shima
S
Minamisawa
Kiwamu
K
Mitsui
Hisayuki
H
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
D005936:Glucans; D005994:Glycerophosphates; D019802:Succinic Acid