Characterization of nonderivatized plant cell walls using high‐resolution solution‐state NMR spectroscopy

Abstract

A recently described plant cell wall dissolution system has been modified to use perdeuterated solvents to allow direct in-NMR-tube dissolution and high-resolution solution-state NMR of the whole cell wall without derivatization. Finely ground cell wall material dissolves in a solvent system containing dimethylsulfoxide-d 6 and 1-methylimidazole-d 6 in a ratio of 4 : 1 (v/v), keeping wood component structures mainly intact in their near-native state. Two-dimensional NMR experiments, using gradient-HSQC (heteronuclear single quantum coherence) 1-bond 13 C-1 H correlation spectroscopy, on nonderivatized cell wall material from a representative gymnosperm Pinus taeda (loblolly pine), an angiosperm Populus tremuloides (quaking aspen), and a herbaceous plant Hibiscus cannabinus (kenaf) demonstrate the efficacy of the system. We describe a method to synthesize 1-methylimidazole-d 6 with a high degree of perdeuteration, thus allowing cell wall dissolution and NMR characterization of nonderivatized plant cell wall structures.

Structural Characterization of Lignin in Wild-Type versus COMT Down-Regulated Switchgrass

“…The central DMSO solvent peak was used for chemical shifts calibration (δc 39.5 ppm, δ H 2.50 ppm). Relative lignin monomer compositions and interunit linkage abundance were estimated semi-quantitatively using volume integration of contours in HSQC spectra (Ralph et al, 2004;Zhang and Gellerstedt, 2007;Kim et al, 2008;Yelle et al, 2008;Jiang et al, 2010;Kim and Ralph, 2010;Samuel et al, 2011;Mansfield et al, 2012). For monolignol compositions of S, G, H, p-coumarate (pCA), and ferulate (FA) measurements, the S 2/6 , G 2 , H 2/6 , pCA 2/6 , and FA 2 contours were used with G 2 and FA 2 integrals doubled (Higuchi et al, 1967;Marita et al, 2001;Ralph et al, 2001Ralph et al, , 2004Capanema et al, 2005;Zhang and Gellerstedt, 2007;Kim et al, 2008;Yelle et al, 2008;Jiang et al, 2010;Kim and Ralph, 2010;Mansfield et al, 2012).…”

Supramolecular Self-Assembled Chaos: Polyphenolic Lignin’s Barrier to Cost-Effective Lignocellulosic Biofuels

“…When MWL isolated using a 4:1(v/v) mixture of dimethylsulfoxide (DMSO) and 1-methylimidazole was used for 2D NMR analysis, the data coupled with nanoindentation became representative of in vivo lignin. The technique of solution state 2D NMR was used for further characterization via heteronuclear single quantum coherence (HSQC) and gave excellent peak separation of aromatic and aliphatic correlations of lignins [171]. Both solid and solution state 2-D NMR techniques are well suited for lignin polymer analyses.…”

HSQC-NMR analysis of lignin in woody (Eucalyptus globulus and Picea abies) and non-woody (Agave sisalana) ball-milled plant materials at the gel state 10th EWLP, Stockholm, Sweden, August 25–28, 2008

“…The original procedure of Lu and Ralph (2003) was later modified and a perdeuterated solvent system was applied to allow a direct in-tube dissolution and solutionstate NMR of the whole cell wall without derivatization (Yelle et al 2008). The solvent system contains NMI-d 6 , which needs to be synthesized.…”