Double-Stranded Helix of Xanthan in Dilute Solution: Evidence from Light Scattering
Double-Stranded Helix of Xanthan in Dilute Solution: Evidence from Light Scattering
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稀溶液中黄原胶的双链螺旋：光散射的证据
DOI：
10.1295/polymj.16.341
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发表时间：
1984
期刊：
影响因子：
2.8
通讯作者：
H. Fujita
中科院分区：
文献类型：
--
作者：
Takahiro Sato;T. Norisuye;H. Fujita
通过光散射研究了黄原胶（一种具有离子侧链的细菌 β-1,4-D-葡聚糖）样品及其在 25°C 0.1 M 氯化钠水溶液和 cadoxen 中的超声处理片段。在这两种溶剂中，回转半径<S2>1/2作为重均分子量Mw的函数，结合大约2的Mw（在0.1M NaCl中）/Mw（在cadoxen中）的比率值，表明黄原胶在0.1M NaCl水溶液中以棒状二聚体形式溶解，在cadoxen中以单柔性链形式溶解。发现黄原胶二聚体的每个主链葡萄糖残基的轮廓长度为0.47±0.01 nm，这与为黄原胶晶体结构提出的51个双链螺旋的螺距（每个葡萄糖残基）一致。因此，得出结论，0.1M NaCl水溶液中的黄原胶二聚体具有51双链螺旋结构。
A sample of xanthan, a bacterial β-1,4-D-glucan with ionic side chains, and its sonicated fragments in 0.1 M aqueous NaCl and cadoxen at 25°C were studied by light scattering. Radii of gyration ‹S2›1/2 as a function of weight-average molecular weight Mw in these two solvents, combined with the values of about 2 for the ratio Mw (in 0.1 M NaCl)/Mw (in cadoxen), showed that xanthan dissolves as rodlike dimers in 0.1 M aqueous NaCl and as single flexible chains in cadoxen. The contour length per main chain glucose residue of the xanthan dimer was found to be 0.47±0.01 nm, which agreed with the pitch (per glucose residue) of the 51 double-stranded helix proposed for the crystalline structure of xanthan. Thus, it was concluded that the xanthan dimer in 0.1 M aqueous NaCl has the 51 double-stranded helical structure.