NMR Studies on the Occurrence of Spirodienone Structures in Lignins

Zhang, Liming; Gellerstedt, Göran; Ralph, John; Lu, Fachuang

doi:10.1080/02773810600580271

Cited by 112 publications

(128 citation statements)

References 24 publications

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“…It contains evidence for the major b-ether units A, resinols C, and, due to the availability of the 5-position for radical coupling in guaiacyl units, phenylcoumaran B and dibenzodioxocin D units. The cortex spectrum, as is typical for S-rich lignins, is particularly rich in b-ether units A, has only low levels of 5-linked (B and D) units, and readily shows the spirodienone units S (from b-1-coupling reactions) that have only recently been authenticated and are most prevalently associated with S-rich lignins (Zhang et al, 2006).…”

Section: Tissue-specific Lignin Analysis In S Moellendorffii Stemmentioning

confidence: 98%

“…Resinols (C) are generally more prevalent in S-rich lignins; their virtual absence in the cortex lignin is most unusual (see Supplemental Figure 1 online). The relatively newly discovered spirodienones S Zhang et al, 2006) are typically more prevalent in S-rich lignins; they are readily seen in the S-rich cortex lignin.…”

Section: Tissue-specific Lignin Analysis In S Moellendorffii Stemmentioning

confidence: 99%

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Independent Recruitment of an O-Methyltransferase for Syringyl Lignin Biosynthesis in Selaginella moellendorffii

et al. 2011

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Syringyl lignin, an important component of the secondary cell wall, has traditionally been considered to be a hallmark of angiosperms because ferns and gymnosperms in general lack lignin of this type. Interestingly, syringyl lignin was also detected in Selaginella, a genus that represents an extant lineage of the most basal of the vascular plants, the lycophytes. In angiosperms, syringyl lignin biosynthesis requires the activity of ferulate 5-hydroxylase (F5H), a cytochrome P450-dependent monooxygenase, and caffeic acid/5-hydroxyferulic acid O-methyltransferase (COMT). Together, these two enzymes divert metabolic flux from the biosynthesis of guaiacyl lignin, a lignin type common to all vascular plants, toward syringyl lignin. Selaginella has independently evolved an alternative lignin biosynthetic pathway in which syringyl subunits are directly derived from the precursors of p-hydroxyphenyl lignin, through the action of a dual specificity phenylpropanoid meta-hydroxylase, Sm F5H. Here, we report the characterization of an O-methyltransferase from Selaginella moellendorffii, COMT, the coding sequence of which is clustered together with F5H at the adjacent genomic locus. COMT is a bifunctional phenylpropanoid O-methyltransferase that can methylate phenylpropanoid meta-hydroxyls at both the 3-and 5-position and function in concert with F5H in syringyl lignin biosynthesis in S. moellendorffii. Phylogenetic analysis reveals that Sm COMT, like F5H, evolved independently from its angiosperm counterparts.

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Section: Tissue-specific Lignin Analysis In S Moellendorffii Stemmentioning

confidence: 98%

Section: Tissue-specific Lignin Analysis In S Moellendorffii Stemmentioning

confidence: 99%

Independent Recruitment of an O-Methyltransferase for Syringyl Lignin Biosynthesis in Selaginella moellendorffii

et al. 2011

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“…NMR spectroscopy provides more precise and comprehensive information on qualitative and quantitative assays for the frequencies of linkages and the composition of H/G/S units in the lignin analysis. The first discovery of dibenzodioxocine and spirodienone structures in lignin was carried out by Ralph et al [66] and Zhang et al [67], respectively. 1 H, 13 C, 19 F, and 31 P as well as various 2D NMR spectroscopic techniques can be used in the structural and compositional analyses of lignin.…”

Section: Ftir Spectroscopy Ftir Spectroscopy Is the Most Widely Usedmentioning

confidence: 99%

Structural Characterization of Lignin and Its Degradation Products with Spectroscopic Methods

Hong-qin

et al. 2017

Journal of Spectroscopy

256

103

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Lignin is highly branched phenolic polymer and accounts 15-30% by weight of lignocellulosic biomass (LCBM). The acceptable molecular structure of lignin is composed with three main constituents linked by different linkages. However, the structure of lignin varies significantly according to the type of LCBM, and the composition of lignin strongly depends on the degradation process. Thus, the elucidation of structural features of lignin is important for the utilization of lignin in high efficient ways. Up to date, degradation of lignin with destructive methods is the main path for the analysis of molecular structure of lignin. Spectroscopic techniques can provide qualitative and quantitative information on functional groups and linkages of constituents in lignin as well as the degradation products. In this review, recent progresses on lignin degradation were presented and compared. Various spectroscopic methods, such as ultraviolet spectroscopy, Fourier-transformed infrared spectroscopy, Raman spectroscopy, and nuclear magnetic resonance (NMR) spectroscopy, for the characterization of structural and compositional features of lignin were summarized. Various NMR techniques, such as 1 H, 13 C, 19 F, and 31 P, as well as 2D NMR, were highlighted for the comprehensive investigation of lignin structure. Quantitative 13 C NMR and various 2D NMR techniques provide both qualitative and quantitative results on the detailed lignin structure and composition produced from various processes which proved to be ideal methods in practice.

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“…Spirodienone correlations Sα, Sβ, and Sβ′ (not shown) were found at 5.14/81.4 ppm, 2.81/60.3 ppm, and 4.18/79.8 ppm. [38,39] Lignin methoxyls, typically a strong and broad contour, show some separation between the guaiacyl and syringyl methoxyls in the aspen and kenaf spectra. [34] ii.…”

Section: Imentioning

confidence: 99%

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

Yelle

Ralph

Frihart

2008

Magnetic Reson in Chemistry

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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.

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NMR Studies on the Occurrence of Spirodienone Structures in Lignins

Cited by 112 publications

References 24 publications

Independent Recruitment of an O-Methyltransferase for Syringyl Lignin Biosynthesis in Selaginella moellendorffii

Independent Recruitment of an O-Methyltransferase for Syringyl Lignin Biosynthesis in Selaginella moellendorffii

Structural Characterization of Lignin and Its Degradation Products with Spectroscopic Methods

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

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