title: Solid-state selective (13)C excitation and spin diffusion NMR to resolve spatial dimensions in plant cell walls.
abstract: The average spatial dimensions between major biopolymers within the plant cell wall can be resolved using a solid-state NMR technique referred to as a (13)C cross-polarization (CP) SELDOM (selectively by destruction of magnetization) with a mixing time delay for spin diffusion. Selective excitation of specific aromatic lignin carbons indicates that lignin is in close proximity to hemicellulose followed by amorphous and finally crystalline cellulose. (13)C spin diffusion time constants (T(SD)) were extracted using a two-site spin diffusion theory developed for (13)C nuclei under magic angle spinning (MAS) conditions. These time constants were then used to calculate an average lower-limit spin diffusion length between chemical groups within the plant cell wall. The results on untreated (13)C enriched corn stover stem reveal that the lignin carbons are, on average, located at distances ∼0.7-2.0 nm from the carbons in hemicellulose and cellulose, whereas the pretreated material had larger separations.
authors.affiliation: BioEnergy Science Center, School of Chemistry and Biochemistry, Institute of Paper Science and Technology, Georgia Institute of Technology, 500 10th Street, Atlanta, Georgia 30332, USA.
authors.forename: Marcus
authors.initials: M
authors.lastname: Foston
authors.forename: Rui
authors.initials: R
authors.lastname: Katahira
authors.forename: Erica
authors.initials: E
authors.lastname: Gjersing
authors.forename: Mark F
authors.initials: MF
authors.lastname: Davis
authors.forename: Arthur J
authors.initials: AJ
authors.lastname: Ragauskas
mesh_terms: D002247:Carbon Isotopes; D002473:Cell Wall / Q000737:chemistry*; D002482:Cellulose / Q000032:analysis / Q000737:chemistry; D008031:Lignin / Q000032:analysis / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D059828:Plant Cells / Q000648:ultrastructure*; D011134:Polysaccharides / Q000032:analysis / Q000737:chemistry; D003313:Zea mays / Q000737:chemistry
chemical_list: D002247:Carbon Isotopes; D011134:Polysaccharides; C007916:hemicellulose; D002482:Cellulose; D008031:Lignin