title: Molecular and crystal structure of galactinol dihydrate [1-O-(alpha-D-galactopyranosyl)-myo-inositol dihydrate].
abstract: The crystal structure of galactinol dihydrate has been determined by X-ray diffraction. The crystal belongs to the orthorhombic system, space group P2(1)2(1)2, a = 15.898(6), b = 19.357(5), c = 5.104(4) A, and Z = 4. The structure was refined to R = 0.044 for 1818 observed structure amplitudes. The primary hydroxyl group exhibits twofold orientational disorder. The linkage conformation is close to those of alpha-(1 --> 4) linkages in methyl alpha-maltotrioside tetrahydrate and erlose trihydrate. Although there is no interring hydrogen bond in galactinol, an indirect interring hydrogen bond including a water molecule is present. The observed conformation is additionally stabilized by the indirect interring hydrogen bond. The global minimum in the relaxed-residue energy map based on the MM3(92) force-field is close to the observed conformation in the crystal structure. All hydroxyl, ring and water oxygen atoms are involved in a complex three-dimensional hydrogen-bonding network.
authors.affiliation: Faculty of Technology, Tokyo University of Agriculture and Technology, Okuyama Laboratory, Koganei, Japan. knoguchi@cc.tuat.ac.jp
authors.forename: K
authors.initials: K
authors.lastname: Noguchi
authors.forename: K
authors.initials: K
authors.lastname: Okuyama
authors.forename: S
authors.initials: S
authors.lastname: Ohno
authors.forename: T
authors.initials: T
authors.lastname: Hidano
authors.forename: N
authors.initials: N
authors.lastname: Wakiuchi
authors.forename: T
authors.initials: T
authors.lastname: Tarui
authors.forename: H
authors.initials: H
authors.lastname: Tamaki
authors.forename: S
authors.initials: S
authors.lastname: Kishihara
authors.forename: S
authors.initials: S
authors.lastname: Fujii
mesh_terms: D002236:Carbohydrate Conformation; D003461:Crystallography; D018360:Crystallography, X-Ray; D004187:Disaccharides / Q000737:chemistry*; D006860:Hydrogen Bonding; D008958:Models, Molecular; D015394:Molecular Structure; D009844:Oligosaccharides / Q000737:chemistry*; D012639:Seeds / Q000737:chemistry; D013816:Thermodynamics; D014867:Water / Q000737:chemistry
chemical_list: D004187:Disaccharides; D009844:Oligosaccharides; D014867:Water; C013536:6 beta-galactinol