title: Molecular ordering of cellulose after extraction of polysaccharides from primary cell walls of Arabidopsis thaliana: a solid-state CP/MAS (13)C NMR study.
abstract: Solid-state CP/MAS 13C NMR spectroscopy was used to determine the effects of three different sequential extraction procedures, used to remove non-cellulosic polysaccharides, on the molecular ordering of cellulose in a cell-wall preparation containing mostly primary cell walls obtained from the leaves of the model dicotyledon, Arabidopsis thaliana. The extractions were 50 mM trans-1,2-diaminocyclohexane N,N,N',N'-tetraacetic acid (CDTA) and 50 mM sodium carbonate (giving Residue 1); 50 mM CDTA, 50 mM sodium carbonate and 1 M KOH (giving Residue 2); and 50 mM CDTA, 50 mM sodium carbonate and 4 M KOH (giving Residue 3). The molecular ordering of cellulose in Residue 1 was similar to that in unextracted walls: the cellulose was almost all crystalline, with 43% of molecules contained in crystallite interiors and similar proportions of the triclinic (I(alpha)) and monoclinic (I(beta)) crystal forms. Residue 2 was partly decrystallized and the remaining crystallites were mostly in the I(beta) form. Residue 3 was a mixture of cellulose II, cellulose I and amorphous cellulose. The presence of signals at 100.0 and 102.3 ppm in the spectra of Residues 1 and 2, but not of unextracted cell walls, suggested that the extractions giving these residues caused some of the non-cellulosic polysaccharides, possibly xyloglucans and galactoglucomannans, to become relatively well ordered, for example through interactions with cellulose crystallite surfaces.
authors.affiliation: School of Biological Sciences, The University of Auckland, Private Bag 92019, Auckland, New Zealand.
authors.forename: Lynette M
authors.initials: LM
authors.lastname: Davies
authors.forename: Philip J
authors.initials: PJ
authors.lastname: Harris
authors.forename: Roger H
authors.initials: RH
authors.lastname: Newman
mesh_terms: D017360:Arabidopsis / Q000737:chemistry*; D002473:Cell Wall / Q000737:chemistry; D002482:Cellulose / Q000737:chemistry* / Q000302:isolation & purification; D003460:Crystallization; D005936:Glucans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008351:Mannans / Q000737:chemistry; D018515:Plant Leaves / Q000737:chemistry; D011134:Polysaccharides / Q000737:chemistry; D014990:Xylans
chemical_list: D005936:Glucans; D008351:Mannans; D011134:Polysaccharides; D014990:Xylans; C443804:galactoglucomannan; C029353:xyloglucan; D002482:Cellulose