title: Folding of xylan onto cellulose fibrils in plant cell walls revealed by solid-state NMR.
abstract: Exploitation of plant lignocellulosic biomass is hampered by our ignorance of the molecular basis for its properties such as strength and digestibility. Xylan, the most prevalent non-cellulosic polysaccharide, binds to cellulose microfibrils. The nature of this interaction remains unclear, despite its importance. Here we show that the majority of xylan, which forms a threefold helical screw in solution, flattens into a twofold helical screw ribbon to bind intimately to cellulose microfibrils in the cell wall.13C solid-state magic-angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy, supported by in silico predictions of chemical shifts, shows both two- and threefold screw xylan conformations are present in fresh Arabidopsis stems. The twofold screw xylan is spatially close to cellulose, and has similar rigidity to the cellulose microfibrils, but reverts to the threefold screw conformation in the cellulose-deficient irx3 mutant. The discovery that induced polysaccharide conformation underlies cell wall assembly provides new principles to understand biomass properties.
authors.affiliation: Department of Biochemistry and Leverhulme Centre for Natural Material Innovation, Hopkins Building, Downing Site, University of Cambridge, Cambridge CB2 1QW, UK.
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Simmons
authors.affiliation: Department of Biochemistry and Leverhulme Centre for Natural Material Innovation, Hopkins Building, Downing Site, University of Cambridge, Cambridge CB2 1QW, UK.
authors.forename: Jenny C
authors.initials: JC
authors.lastname: Mortimer
authors.affiliation: Department of Biochemistry and Leverhulme Centre for Natural Material Innovation, Hopkins Building, Downing Site, University of Cambridge, Cambridge CB2 1QW, UK.|Instituto de Física de São Carlos, Departamento de Física e Ciência Interdisciplinar, Universidade de São Paulo, Caixa Postal 369, São Carlos, Sao needs, São Paulo 13660-970, Brazil.|Department of Physics, University of Warwick, Coventry CV4 7AL, UK.
authors.forename: Oigres D
authors.initials: OD
authors.lastname: Bernardinelli
authors.affiliation: Department of Physics, University of Warwick, Coventry CV4 7AL, UK.
authors.forename: Ann-Christin
authors.initials: AC
authors.lastname: Pöppler
authors.affiliation: Department of Physics, University of Warwick, Coventry CV4 7AL, UK.
authors.forename: Steven P
authors.initials: SP
authors.lastname: Brown
authors.affiliation: Instituto de Física de São Carlos, Departamento de Física e Ciência Interdisciplinar, Universidade de São Paulo, Caixa Postal 369, São Carlos, Sao needs, São Paulo 13660-970, Brazil.
authors.forename: Eduardo R
authors.initials: ER
authors.lastname: deAzevedo
authors.affiliation: Department of Physics, University of Warwick, Coventry CV4 7AL, UK.
authors.forename: Ray
authors.initials: R
authors.lastname: Dupree
authors.affiliation: Department of Biochemistry and Leverhulme Centre for Natural Material Innovation, Hopkins Building, Downing Site, University of Cambridge, Cambridge CB2 1QW, UK.
authors.forename: Paul
authors.identifier: 0000-0001-9270-6286
authors.initials: P
authors.lastname: Dupree
mesh_terms: D017360:Arabidopsis / Q000737:chemistry / Q000235:genetics; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D002247:Carbon Isotopes; D002473:Cell Wall / Q000737:chemistry* / Q000235:genetics; D002482:Cellulose / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D009154:Mutation; D059828:Plant Cells / Q000737:chemistry*; D018547:Plant Stems / Q000737:chemistry / Q000235:genetics; D014990:Xylans / Q000737:chemistry*
chemical_list: D002247:Carbon Isotopes; D014990:Xylans; D002482:Cellulose