Solid-State Selective 13C Excitation and Spin Diffusion NMR To Resolve Spatial Dimensions in Plant Cell Walls
Solid-State Selective 13C Excitation and Spin Diffusion NMR To Resolve Spatial Dimensions in Plant Cell Walls
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DOI：
10.1021/jf204853b
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发表时间：
2012-02-15
影响因子：
6.1
通讯作者：
Ragauskas, Arthur J.
中科院分区：
文献类型：
--
作者：
Foston, Marcus;Katahira, Rui;Ragauskas, Arthur J.
植物细胞壁内主要生物聚合物之间的平均空间尺寸可以使用一种固态核磁共振技术来解决，这种技术被称为C-13交叉极化（CP）很少（选择性地通过磁化破坏），并具有自旋扩散的混合时间延迟。利用魔角自旋（MAS）条件下C-13核的两位点自旋扩散理论，对特定芳香木质素碳的选择性激发表明，木质素与半纤维素的距离较近，其次是无定形纤维素，最后是结晶纤维素。然后用这些时间常数来计算植物细胞壁内化学基团之间的平均下限自旋扩散长度。对未经处理的富含C-13的玉米秸秆茎进行分析，结果表明木质素碳与半纤维素和纤维素碳的平均距离为0.7 ~ 2.0朗姆酒；而预处理后的材料有较大的分离。
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 C-13 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 C-13 spin diffusion time constants (T-SD) were extracted using a two site spin diffusion theory developed for C-13 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 C-13 enriched corn stover stem reveal that the lignin carbons are, on average, located at distances similar to 0.7-2.0 rum from the carbons in hemicellulose and cellulose; whereas the pretreated material had larger separations.