Structure and conformation characterization of galactomannan from seeds of Cassia obtusifolia
Structure and conformation characterization of galactomannan from seeds of Cassia obtusifolia
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DOI：
10.1016/j.foodhyd.2017.06.008
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发表时间：
2018-03-01
影响因子：
10.7
通讯作者：
Xie, Mingyong
中科院分区：
文献类型：
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作者：
Feng, Lei;Yin, Junyi;Xie, Mingyong
采用1D和2D NMR、体积排阻色谱-多检测器联用（SEC-MALS）、动态光散射（DLS）和静态光散射（SLS）等方法，首次系统研究了决明子中性多糖CP-30的精细结构和构象性质。CP-30的结构被阐明为半乳甘露聚糖，由1，4-linked-Manp主链和连接到1，4-linked-Manp的O-6的侧链（T-Galp）组成。DLS和SLS结果表明，0.6 M NaNO 3是CP-30的良好溶剂。结构敏感参数rho（1.33 - 1.80）、Mark-Houwink指数α（0.59）和构象参数v（< Rg>z vs M-w为0.51，R-h vs M-w为0.52）表明CP-30在溶液中为无规卷曲构象。通过蠕虫状圆柱体模型获得的每单位轮廓长度（356.6 nm（-1））、持久长度（5.3 nm）和特征比（24.0）的摩尔质量进一步表明CP-30的致密无规卷曲构象。通过扫描电子显微镜观察，CP-30在水中的线性链形状。本研究对CP-30的结构和构象性质提供了系统的信息，对阐明多糖的理化性质具有重要意义，并对其在食品和医药工业中的进一步应用具有重要意义。(C)2017爱思唯尔有限公司版权所有
The fine structure and conformational properties of neutral polysaccharide isolated from the whole seeds of Cassia obtusifolia (CP-30) were systematically investigated for the first time, by 1D and 2D NMR, size exclusion chromatography coupled with multiple detectors (SEC-MALS), dynamic light scattering (DLS), and static light scattering (SLS). The structure of CP-30 was elucidated to be a galactomannan, consisting of 1,4-linked-Manp backbone with side chains (T-Galp) attached to O-6 of 1,4-linked-Manp. DLS and SLS results showed that 0.6 M NaNO3 was a good solvent for CP-30. The structure sensitive parameter rho (1.33 -1.80), the Mark-Houwink exponent alpha (0.59), and the conformational parameter v (0.51 from < Rg> z vs M-w, and 0.52 from R-h vs M-w) suggested a random coil conformation of CP-30 in solution. The molar mass per unit of contour length (356.6 nm(-1)), persistent length (5.3 nm), and characteristic ratio (24.0) obtained by the wormlike cylinder model further indicated a dense random coil conformation of CP-30. By scanning electron microscopy, the linear chain shape of CP-30 in water was observed. The present research provided systematic information on structural and conformational properties of CP-30, which was important for elucidating the physicochemical characteristics of cassia polysaccharide and meaningful for its further application in food and medicinal industry. (C) 2017 Elsevier Ltd. All rights reserved.