title: X-ray structure analysis of the sodium salt of beijeran.
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.
authors.affiliation: Whistler Center for Carbohydrate Research, 1160 Food Science Building, Purdue University, West Lafayette, IN 47907-1160, USA.
authors.forename: Wen
authors.initials: W
authors.lastname: Bian
authors.forename: Rengaswami
authors.initials: R
authors.lastname: Chandrasekaran
authors.forename: Kozo
authors.initials: K
authors.lastname: Ogawa
mesh_terms: D001395:Azotobacter / Q000737:chemistry*; D002236:Carbohydrate Conformation; D003460:Crystallization; D008958:Models, Molecular; D011135:Polysaccharides, Bacterial / Q000737:chemistry*; D012964:Sodium / Q000737:chemistry*; D014867:Water / Q000737:chemistry; D014961:X-Ray Diffraction / Q000379:methods*
chemical_list: D011135:Polysaccharides, Bacterial; C110945:beijeran; D014867:Water; D012964:Sodium