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Published on: June 8, 2016
X-ray structure analysis of the sodium salt of beijeran
Wen Bian1, Rengaswami Chandrasekaran, Kozo Ogawa
1Whistler Center for Carbohydrate Research, 1160 Food Science Building, Purdue University, West Lafayette, IN 47907-1160, USA.
Abstract:
The three-dimensional structure of the sodium salt of beijeran has been determined by X-ray fiber diffraction analysis. The acidic polysaccharide forms an extended twofold helix. Two chains are nestled tightly in a monoclinic unit cell of dimensions a=12.72, b=11.41, c (fiber axis)=24.62 A and gamma=123.7 degree in an antiparallel fashion. In the crystalline lattice, helices are stacked tightly to form a thick sheet along the vertical plane passing through the short diagonal of the basal net. Adjacent sheets associate via a network of sodium ions and water molecules embedded between them. The morphology of sodium beijeran in the solid state is consistent with its observed rheological properties.
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